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Revision as of 21:55, 15 September 2011 editCheMoBot (talk | contribs)Bots141,565 edits Updating {{chembox}} (no changed fields - added verified revid - updated 'DrugBank_Ref', 'UNII_Ref', 'ChEMBL_Ref', 'KEGG_Ref') per Chem/Drugbox validation (report errors or [[user talk:CheMoBo← Previous edit		Latest revision as of 11:11, 6 January 2025 edit undoRich Farmbrough (talk | contribs)Edit filter managers, Autopatrolled, Extended confirmed users, File movers, Pending changes reviewers, Rollbackers, Template editors1,725,587 edits →Hexagonal form (h-BN)
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			{{Short description|Refractory compound of boron and nitrogen with formula BN}}
			{{primary|date=June 2024}}
			{{expert|Chemicals|date=June 2024}}
	{{Chembox		{{Chembox
			| Verifiedfields = changed
	| verifiedrevid = 447967063
			| Watchedfields = changed
	| ImageFile = Hbncrystals.jpg
			| verifiedrevid = 476994982
	| ImageFile_Ref = {{chemboximage|correct|??}}
			| ImageFile = Hbncrystals.jpg
	| ImageSize = 140
			| ImageFile_Ref = {{chemboximage|correct|??}}
	| ImageName = Magnified sample of crystalline hexagonal boron nitride
			| ImageSize = 140
	| IUPACName = Boron nitride
			| ImageName = Magnified sample of crystalline hexagonal boron nitride
	| Section1 = {{Chembox Identifiers
			| IUPACName = Boron nitride
	| CASNo = 10043-11-5
			| Section1 = {{Chembox Identifiers
	| CASNo_Ref = {{cascite|correct|CAS}}
	| PubChem = 66227		| CASNo = 10043-11-5
	| PubChem_Ref = {{Pubchemcite|correct|pubchem}}		| CASNo_Ref = {{cascite|correct|CAS}}
			| UNII_Ref = {{fdacite|changed|FDA}}
	| ChemSpiderID = 59612
			| UNII = 2U4T60A6YD
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| EINECS = 233-136-6		| PubChem = 66227
	| MeSHName = Elbor		| ChemSpiderID = 59612
	| ChEBI_Ref = {{ebicite|correct|EBI}}		| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
			| EINECS = 233-136-6
			| MeSHName = Elbor
			| ChEBI_Ref = {{ebicite|correct|EBI}}
	| ChEBI = 50883		| ChEBI = 50883
	| RTECS = ED7800000		| RTECS = ED7800000
	| Gmelin = 216		| Gmelin = 216
	| SMILES = B#N		| SMILES = B#N
	| SMILES1 =		| StdInChI = 1S/BN/c1-2
			| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
	| SMILES2 =
	| StdInChI = 1S/BN/c1-2		| InChI = 1S/B2N2/c1-3-2-4-1
			| InChI1 = 1S/B3N3/c1-4-2-6-3-5-1
	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
	| InChI = 1S/B2N2/c1-3-2-4-1		| InChI2 = 1/BN/c1-2
			| StdInChIKey = PZNSFCLAULLKQX-UHFFFAOYSA-N
	| InChI1 = 1S/B3N3/c1-4-2-6-3-5-1
			| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
	| InChI2 = 1/BN/c1-2
	| StdInChIKey = PZNSFCLAULLKQX-UHFFFAOYSA-N		| InChIKey = AMPXHBZZESCUCE-UHFFFAOYSA-N
			| InChIKey1 = WHDCVGLBMWOYDC-UHFFFAOYSA-N
	| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
			| InChIKey2 = PZNSFCLAULLKQX-UHFFFAOYAL
	| InChIKey = AMPXHBZZESCUCE-UHFFFAOYSA-N
	| InChIKey1 = WHDCVGLBMWOYDC-UHFFFAOYSA-N
	| InChIKey2 = PZNSFCLAULLKQX-UHFFFAOYAL
	}}		}}
	| Section2 = {{Chembox Properties		| Section2 = {{Chembox Properties
	| B = 1		| B=1 | N=1
	| N = 1		| MolarMassUnit = g/mol
			| Appearance = Colorless crystals
	| ExactMass = 25.012379471 g mol<sup>−1</sup>
			| Density = 2.1&nbsp;g/cm<sup>3</sup> (h-BN); 3.45&nbsp;g/cm<sup>3</sup> (c-BN)
	| Appearance = Colorless crystals
			| MeltingPtC = 2973
	| Density = 2.1 (hBN); 3.45 (cBN) g cm<sup>−3</sup>
			| MeltingPt_notes = sublimates (c-BN)
	| MeltingPtC = 2973
			| ElectronMobility = 200&nbsp;cm<sup>2</sup>/(V·s) (c-BN)
	| Melting_notes = sublimes (cBN)
			| RefractIndex = 1.8 (h-BN); 2.1 (c-BN)
	| ElectronMobility = 200 cm<sup>2</sup>/(V·s) (cBN)
			| Solubility = Insoluble
	| RefractIndex = 1.8 (hBN); 2.1 (cBN)
	}}		}}
	| Section3 = {{Chembox Structure		| Section3 = {{Chembox Structure
	| CrystalStruct = ], ], ]		| CrystalStruct = ], ], ]
	| Coordination =		| Coordination =
	| MolShape =		| MolShape =
	}}		}}
	| Section4 = {{Chembox Thermochemistry		| Section4 = {{Chembox Thermochemistry
	| DeltaHf = -250.91 kJ mol<sup>−1</sup>		| DeltaHf = −254.4&nbsp;kJ/mol<ref name="auto">for h-BN</ref><ref name=b92t/>
			| DeltaGf = −228.4&nbsp;kJ/mol<ref name="auto"/><ref name=b92t/>
	| Entropy = 14.77 J K<sup>−1</sup> mol<sup>−1</sup>
			| Entropy = 14.8&nbsp;J/K mol<ref name="auto"/><ref name=b92t/>
			| HeatCapacity = 19.7&nbsp;J/(K·mol)<ref name="auto"/><ref name=b92t>{{RubberBible92nd|page=5.6}}</ref>
	}}		}}
	| Section5 = {{Chembox Hazards		| Section5 = {{Chembox Hazards
	| EUClass = {{Hazchem Xi}}		| GHSPictograms = {{GHS07}}
			| GHSSignalWord = Warning
	| NFPA-H = 0
			| HPhrases = {{H-phrases|319|335|413}}
	| NFPA-F = 0
			| PPhrases = {{P-phrases|261|264|271|273|280|304+340|305+351+338|312|337+313|403+233|405|501}}
	| NFPA-R = 0
	| RPhrases = {{R36/37}}		| NFPA-H = 0
			| NFPA-F = 0
	| SPhrases = {{S26}}, {{S36}}
			| NFPA-R = 0
	}}		}}
	| Section8 = {{Chembox Related		| Section8 = {{Chembox Related
			| OtherCompounds = {{ubli
	| OtherCpds = ]<br />
	]<br />		| ]
	]<br />		| ]
	]		| ]
			| ]
			}}
	}}		}}
	}}		}}
	'''Boron nitride''' is a ] with ] BN, consisting of equal numbers of ] and ] atoms. BN is ] to a similarly structured ] lattice and thus exists in various ]. The ] corresponding to ] is the most stable and softest among BN polymorphs, and is therefore used as a lubricant and an additive to cosmetic products. The cubic (]) variety analogous to ] is called c-BN. Its hardness is inferior only to diamond, but its thermal and chemical stability is superior. The rare ] BN modification is similar to ] and may even be harder than the cubic form.		'''Boron nitride''' is a thermally and chemically resistant ] compound of ] and ] with the ] '''BN'''. It exists in various ] that are ] to a similarly structured ] lattice. The ] corresponding to ] is the most stable and soft among BN polymorphs, and is therefore used as a lubricant and an additive to cosmetic products. The cubic (]) variety analogous to ] is called c-BN; it is softer than diamond, but its thermal and chemical stability is superior. The rare ] BN modification is similar to ] but slightly softer than the cubic form.<ref name="ReferenceA">{{Cite journal |arxiv = 1811.09503|doi = 10.1063/1.5082739|title = Myths about new ultrahard phases: Why materials that are significantly superior to diamond in elastic moduli and hardness are impossible|journal = Journal of Applied Physics|volume = 125|issue = 13|pages = 130901|year = 2019|last1 = Brazhkin|first1 = Vadim V.|last2 = Solozhenko|first2 = Vladimir L.|bibcode = 2019JAP...125m0901B|s2cid = 85517548}}</ref>
			Because of excellent thermal and chemical stability, boron nitride ceramics are used in high-temperature equipment and ]. Boron nitride has potential use in nanotechnology.
	Boron nitride is not found in nature and is therefore produced synthetically from ] or ]. The initial product is amorphous BN powder, which is converted to crystalline h-BN by heating in nitrogen flow at temperatures above 1500&nbsp;°C. c-BN is made by ] h-BN powder at higher temperatures, under pressures above 5 GPa. Contrary to diamond, larger c-BN pellets can be produced by fusing (]) relatively cheap c-BN powders. As a result, c-BN is widely used in mechanical applications.
			== History ==
	Because of excellent thermal and chemical stability, boron nitride ceramics are traditionally used as parts of high-temperature equipment. Boron nitride has a great potential in nanotechnology. Nanotubes of BN can be produced that have a structure similar to that of ]s, i.e. graphene (or BN) sheets rolled on themselves, however the properties are very different: whereas carbon nanotubes can be metallic or semiconducting depending on the rolling direction and radius, a BN nanotube is an electrical insulator with a wide bandgap of ~5.5 eV (same as in diamond), which is almost independent of tube chirality and morphology. Similar to other BN forms, BN nanotubes are more thermally and chemically stable than carbon nanotubes which favors them for some applications.
			Boron nitride was discovered by chemistry teacher of the ] {{Ill|William Henry Balmain|de}} in 1842 via reduction of ] with charcoal in the presence of ].<ref>{{Cite journal |last=Balmain |first=W. H. |date=October 1842 |title=Observations on the formation of compounds of boron and silicon with nitrogen and certain metals |url=https://books.google.com/books?id=7XiUObxbsYQC&pg=RA2-PA270 |journal=The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science |language=en |volume=21 |issue=138 |pages=270–277 |doi=10.1080/14786444208621545 |issn=1941-5966}}</ref>
			{{Section-stub|date=November 2024}}
	==Structure==		==Structure==
			Boron nitride exists in multiple forms that differ in the arrangement of the boron and nitrogen atoms, giving rise to varying bulk properties of the material.
	Boron nitride has been produced in an amorphous (a-BN) and crystalline forms. The most stable crystalline form is the hexagonal one, also called h-BN, α-BN, or g-BN (graphitic BN). It has a layered structure similar to graphite. Within each layer, boron and nitrogen atoms are bound by strong ]s, whereas the layers are held together by weak ]s. The interlayer "registry" of these sheets differs, however, from the pattern seen for graphite, because the atoms are eclipsed, with boron atoms lying over and above nitrogen atoms. This registry reflects the polarity of the B-N bonds. Still, h-BN and graphite are very close neighbors and even the BC<sub>6</sub>N hybrids have been synthesized where carbon substitutes for some B and N atoms.<ref>{{cite journal|author =M. Kawaguchi| title = Electronic structure and intercalation chemistry of graphite-like layered material with a composition of BC6N|journal = Journal of Physics and Chemistry of Solids| volume = 69 |year= 2008 |page = 1171| doi = 10.1016/j.jpcs.2007.10.076|last2 =Kuroda|first2 =Shinya|last3 =Muramatsu|first3 =Yasuji|issue =5–6}}</ref>
			=== Amorphous form (a-BN) ===
	As diamond is less stable than graphite, cubic BN is less stable than h-BN, but the conversion rate between those forms is negligible at room temperature. The cubic form has the sphalerite crystal structure, same as diamond structure, and is also called β-BN or c-BN. The ] BN form (w-BN) has similar structure as lonsdaleite, rare hexagonal polymorph of carbon. In both c-BN and w-BN boron and nitrogen atoms are grouped into ], but the angles between neighboring tetrahedra are different.<ref>{{cite book| author = M. S. Silberberg |title = Chemistry: The Molecular Nature of Matter and Change, Fifth Edition |publisher = New York: McGraw-Hill |year = 2009 |page = 483}}</ref>
			The amorphous form of boron nitride (a-BN) is non-crystalline, lacking any long-distance regularity in the arrangement of its atoms. It is analogous to ].
			All other forms of boron nitride are crystalline.
	{|align="center" class="wikitable"
	|<center>]</center>||<center>]</center>||<center>]
			=== Hexagonal form (h-BN) ===
	|-
			The most stable crystalline form is the hexagonal one, also called h-BN, α-BN, g-BN, graphitic boron nitride and "white graphene". Hexagonal boron nitride (point group = D<sub>3h</sub>; space group = P6<sub>3</sub>/mmc) has a layered structure similar to graphite. Within each layer, boron and nitrogen atoms are bound by strong ]s, whereas the layers are held together by weak ]s. The interlayer "registry" of these sheets differs, however, from the pattern seen for graphite, because the atoms are eclipsed, with boron atoms lying over and above nitrogen atoms. This registry reflects the local polarity of the B–N bonds, as well as interlayer N-donor/B-acceptor characteristics. Likewise, many metastable forms consisting of differently stacked polytypes exist. Therefore, h-BN and graphite are very close neighbors, and the material can accommodate carbon as a substituent element to form BNCs. BC<sub>6</sub>N hybrids have been synthesized, where carbon substitutes for some B and N atoms.<ref>{{cite journal | author = Kawaguchi, M. | title = Electronic Structure and Intercalation Chemistry of Graphite-Like Layered Material with a Composition of BC6N | journal = Journal of Physics and Chemistry of Solids | volume = 69 | year = 2008 | page = 1171 | doi = 10.1016/j.jpcs.2007.10.076 |issue = 5–6 |bibcode = 2008JPCS...69.1171K |display-authors=etal}}</ref> Hexagonal boron nitride monolayer is analogous to ], having a honeycomb lattice structure of nearly the same dimensions. Unlike graphene, which is black and an electrical conductor, h-BN monolayer is white and an insulator. It has been proposed for use as an atomic flat insulating substrate or a ] dielectric barrier in 2D electronics. .<ref>{{cite journal
	|<center>α-BN, hexagonal</center>||<center>β-BN, ] structure</center>||<center>BN, ] structure</center>
			| vauthors = Ba K, Jiang W, Cheng J, Bao J, ''et al.''
	|}
			| date = 2017
			| title = Chemical and Bandgap Engineering in Monolayer Hexagonal Boron Nitride
			| journal = Scientific Reports
			| volume = 7
			| issue = 1
			| page = 45584
			| doi = 10.1038/srep45584
			| pmid = 28367992
			| bibcode = 2017NatSR...745584B
			| s2cid = 22951232
			| doi-access = free
			| pmc = 5377335
			}}</ref>
			=== Cubic form (c-BN) ===
			Cubic boron nitride has a crystal structure analogous to that of ]. Consistent with diamond being less stable than graphite, the cubic form is less stable than the hexagonal form, but the conversion rate between the two is negligible at room temperature, as it is for diamond. The cubic form has the ] (space group = F{{overline|4}}3m), the same as that of diamond (with ordered B and N atoms), and is also called β-BN or c-BN.
			=== Wurtzite form (w-BN) ===
			The ] form of boron nitride (w-BN; point group = C<sub>6v</sub>; space group = P6<sub>3</sub>mc) has the same structure as ], a rare hexagonal polymorph of carbon. As in the cubic form, the boron and nitrogen atoms are grouped into ].<ref>{{cite book | author = Silberberg, M. S. | title = Chemistry: The Molecular Nature of Matter and Change | edition = 5th | location = New York | publisher = McGraw-Hill | year = 2009 | page = 483 |isbn=978-0-07-304859-8}}</ref> In the wurtzite form, the boron and nitrogen atoms are grouped into 6-membered rings. In the cubic form all rings are in the ], whereas in w-BN the rings between 'layers' are in ]. Earlier optimistic reports predicted that the wurtzite form was very strong, and was estimated by a simulation as potentially having a strength 18% stronger than that of diamond. Since only small amounts of the mineral exist in nature, this has not yet been experimentally verified.<ref>{{Cite web |url=https://www.newscientist.com/article/dn16610-diamond-no-longer-natures-hardest-material/ |title=Diamond no longer nature's hardest material |last=Griggs |first=Jessica |date=2014-05-13 |website=New Scientist |access-date=2018-01-12}}</ref> Its hardness is 46 GPa, slightly harder than commercial borides but softer than the cubic form of boron nitride.<ref name="ReferenceA" />
			<gallery mode="packed">
			File:Boron-nitride-(hexagonal)-side-3D-balls.png|Hexagonal form (h-BN)<br/>] analogous to ]
			File:Boron-nitride-(sphalerite)-3D-balls.png|Cubic form (c-BN)<br/>] structure<br/> analogous to ]
			File:Boron-nitride-(wurtzite)-3D-balls.png|Wurtzite form (w-BN)<br/>] structure<br/>analogous to ]
			</gallery>
			== Properties ==
	==Properties==
	===Physical===		===Physical===
	{| class="wikitable" border="1" cellpadding="3" cellspacing="0" style="margin:0px"		{| class="wikitable" style="margin:0;"
	|+ Properties of amorphous and crystalline BN, graphite and diamond.<br /><small>Some properties of h-BN and graphite differ within the basal planes (║) and perpendicular to them (╧)</small>		|+ Properties of amorphous and crystalline BN, graphite and diamond.<br /><small>Some properties of h-BN and graphite differ within the basal planes (∥) and perpendicular to them (⟂)</small>
	!Material		! rowspan=2 | Material
			! colspan=4 | Boron nitride (BN)
	!a-BN
			! rowspan=2 | Graphite<ref>{{cite book | author = Delhaes, P. | title = Graphite and Precursors | publisher = CRC Press | year = 2001 | isbn = 978-9056992286}}</ref>
	!h-BN
			! rowspan=2 | Diamond<ref name=ioffe>{{cite web | url = http://www.ioffe.ru/SVA/NSM/Semicond/BN/index.html | title = BN – Boron Nitride | work = Ioffe Institute Database}}</ref>
	!c-BN
	!w-BN
	!graphite
	!diamond
	|-		|-
			! a-<ref>{{cite journal | doi = 10.1016/0022-3093(95)00748-2 | title = Properties of Amorphous Boron Nitride Thin Films | year = 1996 | author = Zedlitz, R. | journal = Journal of Non-Crystalline Solids | volume = 198–200 | issue = Part 1 | page = 403 |bibcode = 1996JNCS..198..403Z}}</ref><ref>{{cite journal | doi = 10.1364/AO.32.000091 | pmid = 20802666 | title = Thermal Conductivities of Thin, Sputtered Optical Films | year = 1993 | author = Henager, C. H. Jr. | journal = Applied Optics | volume = 32 | issue = 1 | pages = 91–101 |bibcode = 1993ApOpt..32...91H | url = https://digital.library.unt.edu/ark:/67531/metadc1108231/}}</ref><ref>{{cite journal | doi = 10.1016/S0925-9635(98)00394-X | title = Microstructure and Mechanical Properties of Pulsed Laser Deposited Boron Nitride Films | year = 1999 | author = Weissmantel, S. | journal = Diamond and Related Materials | volume = 8 | page = 377 | issue = 2–5 |bibcode = 1999DRM.....8..377W}}</ref>
	!Density (g/cm<sup>3</sup>)
			! h-
	|2.28
			! c-<ref name=BN>{{cite book | title = Landolt-Börnstein – Group VIII Advanced Materials and Technologies: Powder Metallurgy Data. Refractory, Hard and Intermetallic Materials | chapter = 13.5 Properties of diamond and cubic boron nitride | volume = 2A2 | doi = 10.1007/b83029 | isbn = 978-3-540-42961-6 | pages = 118–139 | editor = P. Beiss | author = Leichtfried, G. | year = 2002 | publisher = Springer | location = Berlin |display-authors=etal|display-editors=etal| series = Landolt-Börnstein - Group VIII Advanced Materials and Technologies}}</ref><ref name=ioffe/>
	|~2.1
			! w-
	|3.45
	|3.49
	|~2.1
	|3.515
	|-		|-
			! Density (g/cm<sup>3</sup>)
	!]
			| 2.28
	|
			| ~2.1
	|1–2
			| 3.45
	|~10
			| 3.49
	|~10
			| ~2.1
	|1–2
			| 3.515
	|10
	|-		|-
	!] (GPa)		! ] (GPa)
	|10		| 10
	|		|
	|45		| 45
	|34		| 34
	|		|
	|100		| 100
	|-		|-
	!] (GPa)		! ] (GPa)
	|100		| 100
	|36.5		| 36.5
	|400		| 400
	|400		| 400
	|34		| 34
	|440		| 440
	|-		|-
	!] (W/cm K)		! ] <br/>(W/m·K)
			| 3
	|0.03
			| 600 ∥, <br/>30 ⟂
	|6║; 0.3 ┴
			| 740
	|7.4
	|		|
			| 200–2000 ∥, <br/>2–800 ⟂
	|2–20║; 0.02–0.8┴
			| 600–2000
	|6–20
	|-		|-
	!] (10<sup>−6</sup>/°C)		! ] (10<sup>−6</sup>/K)
	|		|
	| −2.7║; 38┴		| −2.7 ∥, 38 ⟂
	|1.2		| 1.2
	|2.7		| 2.7
	| −1.5║; 25┴		| −1.5 ∥, 25 ⟂
	|0.8		| 0.8
	|-		|-
	!] (eV)		! ] (eV)
	|5.05		| 5.05
			| 5.9–6.4 <ref>{{cite journal |author=Su, C. | title = Tuning colour centres at a twisted hexagonal boron nitride interface | journal = Nature Materials | volume = 21 | year = 2022 | issue = 8 | pages = 896–902 | doi = 10.1038/s41563-022-01303-4| pmid = 35835818 | bibcode = 2022NatMa..21..896S | osti = 1906698 | s2cid = 250535073 | url = https://escholarship.org/uc/item/98b013nr}}</ref>
	|5.2
			| 10.1-10.7 <ref>{{cite journal |author1= Tararan, Anna |author2=di Sabatino, Stefano |author3=Gatti, Matteo |author4=Taniguchi, Takashi |author5=Watanabe, Kenji |author6=Reining, Lucia |author7=Tizei, Luiz H. G. |author8=Kociak, Mathieu |author9=Zobelli, Alberto| title = Optical gap and optically active intragap defects in cubic BN | journal = Phys. Rev. B | volume = 98| year = 2018| issue = 9 | pages = 094106 | doi =10.1103/PhysRevB.98.094106 | arxiv = 1806.11446 | bibcode = 2018PhRvB..98i4106T | s2cid = 119097213 | url = https://journals.aps.org/prb/abstract/10.1103/PhysRevB.98.094106}}</ref>
	|6.4
	|4.5–5.5		| 4.5–5.5
	|0		| 0
	|5.5		| 5.5
	|-		|-
	!]		! ]
	|1.7		| 1.7
	|1.8		| 1.8
	|2.1		| 2.1
	|2.05		| 2.05
	|		|
	|2.4		| 2.4
	|-		|-
	!] (µemu/g)<ref>{{cite journal| author = T. P. Crane and B. P. Cowan| title= Magnetic relaxation properties of helium-3 adsorbed on hexagonal boron nitride| journal = Phys. Rev. B |volume = 62 |page = 11359 |year = 2000| doi = 10.1103/PhysRevB.62.11359| issue = 17}}</ref>		! ] <br/>(µemu/g)<ref>{{cite journal |author1=Crane, T. P. |author2=Cowan, B. P. | title = Magnetic Relaxation Properties of Helium-3 Adsorbed on Hexagonal Boron Nitride | journal = Physical Review B | volume = 62 | page = 11359 | year = 2000 | doi = 10.1103/PhysRevB.62.11359 | issue = 17 |bibcode = 2000PhRvB..6211359C}}</ref>
	|		|
	| −0.48║; -17.3┴		| −0.48 ∥, <br/>−17.3 ⟂
	|		|
	|		|
			| −0.2 – −2.7 ∥, <br/>−20 – −28 ⟂
	| −0.2..-2.7║; -20..-28┴
	| −1.6		| −1.6
	|-
	|}		|}
	''Sources: amorphous BN,<ref>{{cite journal|doi =10.1016/0022-3093(95)00748-2|title =Properties of amorphous boron nitride thin films|year =1996|author =R. Zedlitz|journal =Journal of Non-Crystalline Solids|volume =198–200|pages =403}}</ref><ref>{{cite journal|doi =10.1364/AO.32.000091|pmid =20802666|title =Thermal conductivities of thin, sputtered optical films|year =1993|author =C. H. Henager, Jr.|journal =Applied Optics|volume =32|issue =1|pages =91}}</ref><ref>{{cite journal|doi =10.1016/S0925-9635(98)00394-X|title =Microstructure and mechanical properties of pulsed laser deposited boron nitride films|year =1999|author =S. Weissmantel|journal =Diamond and Related Materials|volume =8|pages =377|issue =2–5}}</ref> crystalline BN,<ref name=BN>{{cite book| title = Landolt-Börnstein – Group VIII Advanced Materials and Technologies: Powder Metallurgy Data. Refractory, Hard and Intermetallic Materials| chapter = 13.5 Properties of diamond and cubic boron nitride|volume = 2A2| doi = 10.1007/b83029| isbn = 978-3-540-42961-6| pages = 118–139| author = ed.: P. Beiss ''et al.'', Authors: G. Leichtfried ''et al.''| year = 2002| publisher = Springer| location = Berlin}}</ref><ref name=ioffe/> graphite,<ref>{{cite book| author = P. Delhaes| title = Graphite and Precursors| publisher = CRC Press| year =2001| isbn = 9056992287}}</ref> diamond''.<ref name=ioffe>{{cite web| url= http://www.ioffe.ru/SVA/NSM/Semicond/BN/index.html| title=Ioffe database| accessdate=2009-05-05}}</ref>
	{{clear}}		{{clear}}
	The partly ] structure of BN layers in h-BN reduces covalency and electrical conductivity, whereas the interlayer interaction increases resulting in higher hardness of h-BN relative to graphite. The reduced electron-delocalization in hexagonal-BN is also indicated by its absence of color and a large ]. Very different bonding – strong covalent within the ]s (planes where boron and nitrogen atoms are covalently bonded) and weak between them – causes high ] of most properties of h-BN.		The partly ] structure of BN layers in h-BN reduces covalency and electrical conductivity, whereas the interlayer interaction increases resulting in higher hardness of h-BN relative to graphite. The reduced electron-delocalization in hexagonal-BN is also indicated by its absence of color and a large ]. Very different bonding – strong covalent within the ]s (planes where boron and nitrogen atoms are covalently bonded) and weak between them – causes high ] of most properties of h-BN.
	For example, the hardness, electrical and thermal conductivity are much higher within the planes than perpendicular to them. On the contrary, the properties of c-BN and w-BN are more homogeneous.		For example, the hardness, electrical and thermal conductivity are much higher within the planes than perpendicular to them. On the contrary, the properties of c-BN and w-BN are more homogeneous and isotropic.
	Those materials are extremely hard, with the hardness of c-BN being slightly smaller and w-BN even higher than that of diamond.<ref>{{cite journal| author =Z. Pan |title = Harder than Diamond: Superior Indentation Strength of Wurtzite BN and Lonsdaleite| journal=Physical Review Letters |volume = 102 |page = 055503 |year =2009 |doi =10.1103/PhysRevLett.102.055503| last2 =Sun| first2 =Hong| last3 =Zhang| first3 =Yi| last4 =Chen| first4 =Changfeng | pmid=19257519 | bibcode=2009PhRvL.102e5503P| issue =5}}</ref> Because of much better stability to heat and metals, c-BN surpasses diamond in mechanical applications.<ref name=dkg>{{cite journal| title = Hexagonal Boron Nitride (hBN) – Applications from Metallurgy to Cosmetics| url = http://www.esk.com/uploads/tx_userjspresseveroeff/PR_0712_CFI_12-2007_Hexagonales-BN_e_01.pdf| author =M. Engler| journal = Cfi/Ber. DKG |volume = 84|year = 2007| page = D25| issn = 0173-9913}}</ref> The thermal conductivity of BN is among the highest of all electric insulators (see table).		Those materials are extremely hard, with the hardness of bulk c-BN being slightly smaller and w-BN even higher than that of diamond.<ref>{{cite journal | author = Pan, Z. | title = Harder than Diamond: Superior Indentation Strength of Wurtzite BN and Lonsdaleite | journal = Physical Review Letters | volume = 102 | page = 055503 | year = 2009 | doi = 10.1103/PhysRevLett.102.055503 | pmid = 19257519 | bibcode = 2009PhRvL.102e5503P | issue = 5 |display-authors=etal}}</ref> Polycrystalline c-BN with grain sizes on the order of 10&nbsp;nm is also reported to have ] comparable or higher than diamond.<ref>{{cite journal|author=Tian, Yongjun |doi=10.1038/nature11728|title=Ultrahard nanotwinned cubic boron nitride|year=2013|journal=Nature|volume=493|issue=7432|pages=385–8|pmid=23325219|display-authors=etal|bibcode = 2013Natur.493..385T |s2cid=4419843}}</ref> Because of much better stability to heat and transition metals, c-BN surpasses diamond in mechanical applications, such as machining steel.<ref name=dkg>{{cite journal | title = Hexagonal Boron Nitride (hBN) – Applications from Metallurgy to Cosmetics | url = http://www.esk.com/uploads/tx_userjspresseveroeff/PR_0712_CFI_12-2007_Hexagonales-BN_e_01.pdf | author = Engler, M. | journal = Cfi/Ber. DKG | volume = 84 | year = 2007 | page = D25 | issn = 0173-9913}}</ref> The thermal conductivity of BN is among the highest of all electric insulators (see table).
	Boron nitride can be doped p-type with Be and n-type with boron, sulfur, silicon or if co-doped with carbon and nitrogen.<ref name=BN/> Both hexagonal and cubic BN are wide-gap semiconductors with a band gap energy corresponding to the UV region. If voltage is applied to h-BN <ref>{{cite journal |author = Y. Kubota|title = Deep Ultraviolet Light-Emitting Hexagonal Boron Nitride Synthesized at Atmospheric Pressure| doi = 10.1126/science.1144216 |journal = Science |pmid = 17702939 |volume = 317 |issue = 5840|year = 2007 |page = 932 |last2 = Watanabe |first2 = K. |last3 = Tsuda |first3 = O. |last4 = Taniguchi |first4 = T.}}</ref><ref name="taniguchi">{{cite journal| author = K. Watanabe, T. Taniguchi, H. Kanda |title = Direct-bandgap properties and evidence for ultraviolet lasing of hexagonal boron nitride single crystal| doi = 10.1038/nmat1134 |journal = Nature Materials| pmid = 15156198 |volume = 3| issue = 6 |year = 2004 |page = 404}}</ref> or c-BN,<ref>{{cite journal| author =T. Taniguchi |title =Ultraviolet light emission from self-organized p–n domains in cubic boron nitride bulk single crystals grown under high pressure| doi = 10.1063/1.1524295 |journal = Appl. Phys. Lett.|volume = 81 |year =2002 |page = 4145| last2 =Watanabe| first2 =K.| last3 =Koizumi| first3 =S.| last4 =Sakaguchi| first4 =I.| last5 =Sekiguchi| first5 =T.| last6 =Yamaoka| first6 =S.| issue =22}}</ref> then it emits UV light in the range 215–250&nbsp;nm and therefore can potentially be used as ] (LEDs) or lasers.		Boron nitride can be doped p-type with beryllium and n-type with boron, sulfur, silicon or if co-doped with carbon and nitrogen.<ref name=BN/> Both hexagonal and cubic BN are wide-gap semiconductors with a band-gap energy corresponding to the UV region. If voltage is applied to h-BN<ref>{{cite journal | author = Kubota, Y. | title = Deep Ultraviolet Light-Emitting Hexagonal Boron Nitride Synthesized at Atmospheric Pressure | doi = 10.1126/science.1144216 | journal = Science | pmid = 17702939 | volume = 317 | issue = 5840 | year = 2007 | pages = 932–4 |bibcode = 2007Sci...317..932K |display-authors=etal| doi-access = free}}</ref><ref name="taniguchi">{{cite journal |author1=Watanabe, K. |author2=Taniguchi, T. |author3=Kanda, H. | title = Direct-Bandgap Properties and Evidence for Ultraviolet Lasing of Hexagonal Boron Nitride Single Crystal | doi = 10.1038/nmat1134 | journal = Nature Materials | pmid = 15156198 | volume = 3 | issue = 6 | year = 2004 | pages = 404–9 |bibcode = 2004NatMa...3..404W |s2cid=23563849}}</ref> or c-BN,<ref>{{cite journal | author = Taniguchi, T. | title = Ultraviolet Light Emission from Self-Organized p–n Domains in Cubic Boron Nitride Bulk Single Crystals Grown Under High Pressure | doi = 10.1063/1.1524295 | journal = Applied Physics Letters | volume = 81 | year = 2002 | page = 4145 | issue = 22 |bibcode = 2002ApPhL..81.4145T |display-authors=etal}}</ref> then it emits UV light in the range 215–250&nbsp;nm and therefore can potentially be used as ]s (LEDs) or lasers.
	Little is known on melting behavior of boron nitride. It sublimates at 2973&nbsp;°C at normal pressure releasing nitrogen gas and boron, but melts at elevated pressure.<ref>{{cite journal|doi =10.1021/j100814a515|year =1962|author =Lloyd H. Dreger|journal =The Journal of Physical Chemistry|volume =66|pages =1556|last2 =Dadape|first2 =V. V.|last3 =Margrave|first3 =John L.|issue =8}}</ref><ref name=wentorf/>		Little is known on melting behavior of boron nitride. It degrades at 2973&nbsp;°C, but melts at elevated pressure.<ref>{{cite journal | doi = 10.1021/j100814a515 | title = Sublimation and Decomposition Studies on Boron Nitride and Aluminum Nitride | year = 1962 | author = Dreger, Lloyd H. | journal = The Journal of Physical Chemistry | volume = 66 | page = 1556 | issue = 8 |display-authors=etal}}</ref><ref name=wentorf1957>{{cite journal | doi = 10.1063/1.1745964 | title = Cubic Form of Boron Nitride | year = 1957 | author= Wentorf, R. H. | journal = The Journal of Chemical Physics | volume = 26 | issue = 4 | page = 956 | bibcode=1957JChPh..26..956W}}</ref>
	===Thermal stability===		===Thermal stability===
	Hexagonal and cubic (and probably w-BN) BN show remarkable chemical and thermal stabilities. For example, h-BN is stable to decomposition in temperatures up to 1000&nbsp;°C in air, 1400&nbsp;°C in vacuum, and 2800&nbsp;°C in an inert atmosphere. The reactivity of h-BN and c-BN is relatively similar, and the data for c-BN are summarized in the table below.		Hexagonal and cubic BN (and probably w-BN) show remarkable chemical and thermal stabilities. For example, h-BN is stable to decomposition at temperatures up to 1000&nbsp;°C in air, 1400&nbsp;°C in vacuum, and 2800&nbsp;°C in an inert atmosphere. The reactivity of h-BN and c-BN is relatively similar, and the data for c-BN are summarized in the table below.
	{| class="wikitable" border="1" cellpadding="3" cellspacing="0" style="margin:10px"		{| class="wikitable" style="margin:10px;"
	|+ Reactivity of c-BN with solids<ref name=BN/>		|+ Reactivity of c-BN with solids<ref name=BN/>
	!Solid		! Solid
	!Ambient		! Ambient
	!Action		! Action
	!Threshold T (°C)		! Threshold temperature (°C)
	|-		|-
	|Mo		| Mo
	|10<sup>−2</sup> Pa vacuum		| {{val|e=-2|u=Pa}} vacuum
			| Reaction
	|reaction
	|1360		| 1360
	|-		|-
	|Ni		| Ni
	|10<sup>−2</sup> Pa vacuum		| {{val|e=-2|u=Pa}} vacuum
	|]<ref>Here wetting refers to the ability of a molten metal to keep contact with solid BN</ref>		| ]{{efn|Here wetting refers to the ability of a molten metal to keep contact with solid BN}}
	|1360		| 1360
	|-		|-
	|Fe, Ni, Co		| Fe, Ni, Co
	|argon		| Argon
			| React
	|react
	|1400–1500		| 1400–1500
	|-		|-
	|Al		| Al
	|10<sup>−2</sup> Pa vacuum		| {{val|e=-2|u=Pa}} vacuum
	|wetting and reaction		| Wetting and reaction
	|1050		| 1050
	|-		|-
	|Si		| Si
	|10<sup>−3</sup> Pa vacuum		| {{val|e=-3|u=Pa}} vacuum
			| Wetting
	|wetting
	|1500		| 1500
	|-		|-
	|Cu, Ag, Au, Ga, In, Ge, Sn		| Cu, Ag, Au, Ga, In, Ge, Sn
	|10<sup>−3</sup> Pa vacuum		| {{val|e=-3|u=Pa}} vacuum
	|no wetting		| No wetting
	|1100		| 1100
	|-		|-
	|B		| B
	|		|
	|no wetting		| No wetting
	|2200		| 2200
	|-		|-
			| {{chem2|Al2O3 + B2O3}}
	|Al<sub>2</sub>O<sub>3</sub> + B<sub>2</sub>O<sub>3</sub>
	|10<sup>−2</sup> Pa vacuum		| {{val|e=-2|u=Pa}} vacuum
	|no reaction		| No reaction
	|1360		| 1360
	|}		|}
	{{clear}}		{{clear}}
	Thermal stability of c-BN can be summarized as follows:<ref name=BN/>		Thermal stability of c-BN can be summarized as follows:<ref name=BN/>
	*In air or oxygen: B<sub>2</sub>O<sub>3</sub> protective layer prevents further oxidation to ~1300&nbsp;°C; no conversion to hexagonal form at 1400&nbsp;°C.		* In air or oxygen: {{chem2|B2O3}} protective layer prevents further oxidation to ~1300&nbsp;°C; no conversion to hexagonal form at 1400&nbsp;°C.
	*In nitrogen: some conversion to h-BN at 1525&nbsp;°C after 12 h.		* In nitrogen: some conversion to h-BN at 1525&nbsp;°C after 12&nbsp;h.
	*In vacuum (10<sup>−5</sup> Pa): conversion to h-BN at 1550–1600&nbsp;°C.		* In vacuum ({{val|e=-5|u=Pa}}): conversion to h-BN at 1550–1600&nbsp;°C.
	===Chemical stability===		===Chemical stability===
	Boron nitride is insoluble in usual acids, but is soluble in alkaline molten salts and nitrides, such as LiOH, KOH, NaOH-Na<sub>2</sub>CO<sub>3</sub>, NaNO<sub>3</sub>, Li<sub>3</sub>N, Mg<sub>3</sub>N<sub>2</sub>, Sr<sub>3</sub>N<sub>2</sub>, Ba<sub>3</sub>N<sub>2</sub> or Li<sub>3</sub>BN<sub>2</sub>, which are therefore used to etch BN.<ref name=BN/>		Boron nitride is not attacked by the usual acids, but it is soluble in alkaline molten salts and nitrides, such as ], ], ]-], ], ], ], ], ] or ], which are therefore used to etch BN.<ref name=BN/>
	===Thermal conductivity===		===Thermal conductivity===
	The theoretical thermal conductivity of hexagonal Boron nitride nanoribbons (BNNRs) can approach 1700–2000 W/(m·K), which has the same order of magnitude as the experimental measured value for ], and can be comparable to the theoretical calculations for graphene nanoribbons.<ref>{{cite journal |author = J. H. Lan ''et al.''|title = Thermal transport in hexagonal boron nitride nanoribbons | doi = 10.1103/PhysRevB.79.115401|journal = Physical Review B |volume = 79 |issue = 11 |year = 2009 |page = 115401}}</ref><ref>{{cite journal |author = Jiuning Hu, Xiulin Ruan and Yong P. Chen|title = Thermal Conductivity and Thermal Rectification in Graphene Nanoribbons: A Molecular Dynamics Study | doi = 10.1021/nl901231s|journal = Nano Lett. |volume = 9 |issue = 7 |year = 2009 |page = 2730 |pmid=19499898}}</ref> Moreover, the thermal transport in the BNNRs is anisotropic. The thermal conductivity of zigzag-edged BNNRs is about 20% larger than that of armchair-edged nanoribbons at room temperature.<ref>{{cite journal |author = Tao Ouyang, Yuanping Chen, Yuee Xie, Kaike Yang, Zhigang Bao and Jianxin Zhong|title = Thermal transport in hexagonal boron nitride nanoribbons | doi = 10.1088/0957-4484/21/24/245701|journal = Nanotechnology |volume = 21 |issue = 24|year = 2010 |page = 245701}}</ref>		The theoretical thermal conductivity of hexagonal boron nitride nanoribbons (BNNRs) can approach 1700–2000&nbsp;]/(]⋅]), which has the same order of magnitude as the experimental measured value for ], and can be comparable to the theoretical calculations for graphene nanoribbons.<ref>{{cite journal | author = Lan, J. H. | title = Thermal Transport in Hexagonal Boron Nitride Nanoribbons | doi = 10.1103/PhysRevB.79.115401 | journal = Physical Review B | volume = 79 | issue = 11 | year = 2009 | page = 115401 |bibcode = 2009PhRvB..79k5401L |display-authors=etal}}</ref><ref>{{cite journal | vauthors = Hu J, Ruan X, Chen YP| title = Thermal Conductivity and Thermal Rectification in Graphene Nanoribbons: A Molecular Dynamics Study | doi = 10.1021/nl901231s| journal = Nano Letters | volume = 9 | issue = 7 | year = 2009 | pages = 2730–5 | pmid = 19499898 |arxiv = 1008.1300 |bibcode = 2009NanoL...9.2730H | s2cid = 1157650}}</ref> Moreover, the thermal transport in the BNNRs is ]. The thermal conductivity of zigzag-edged BNNRs is about 20% larger than that of armchair-edged nanoribbons at room temperature.<ref>{{cite journal | title = Thermal Transport in Hexagonal Boron Nitride Nanoribbons | doi = 10.1088/0957-4484/21/24/245701 | pmid = 20484794 | journal = Nanotechnology | volume = 21 | issue = 24 | year = 2010 | page = 245701 |bibcode = 2010Nanot..21x5701O | last1 = Ouyang | first1 = Tao | last2 = Chen | first2 = Yuanping | last3 = Xie | first3 = Yuee | last4 = Yang | first4 = Kaike | last5 = Bao | first5 = Zhigang | last6 = Zhong | first6 = Jianxin | s2cid = 12898097}}</ref>
			=== Mechanical properties ===
	==Synthesis==
			BN nanosheets consist of hexagonal boron nitride (h-BN). They are stable up to 800°C in air. The structure of monolayer BN is similar to that of ], which has exceptional strength,<ref name=":0">{{Cite journal |last1=Falin |first1=Aleksey |last2=Cai |first2=Qiran |last3=Santos |first3=Elton J. G. |last4=Scullion |first4=Declan |last5=Qian |first5=Dong |last6=Zhang |first6=Rui |last7=Yang |first7=Zhi |last8=Huang |first8=Shaoming |last9=Watanabe |first9=Kenji |last10=Taniguchi |first10=Takashi |last11=Barnett |first11=Matthew R. |last12=Chen |first12=Ying |last13=Ruoff |first13=Rodney S. |last14=Li |first14=Lu Hua |date=2017-06-22 |title=Mechanical properties of atomically thin boron nitride and the role of interlayer interactions |journal=Nature Communications |language=en |volume=8 |issue=1 |pages=15815 |doi=10.1038/ncomms15815 |pmid=28639613 |pmc=5489686 |issn=2041-1723|arxiv=2008.01657 |bibcode=2017NatCo...815815F }}</ref> a high-temperature lubricant, and a substrate in electronic devices.<ref>{{Cite journal |last1=Bosak |first1=Alexey |last2=Serrano |first2=Jorge |last3=Krisch |first3=Michael |last4=Watanabe |first4=Kenji |last5=Taniguchi |first5=Takashi |last6=Kanda |first6=Hisao |date=2006-01-19 |title=Elasticity of hexagonal boron nitride: Inelastic x-ray scattering measurements |url=https://link.aps.org/doi/10.1103/PhysRevB.73.041402 |journal=Physical Review B |language=en |volume=73 |issue=4 |page=041402 |doi=10.1103/PhysRevB.73.041402 |bibcode=2006PhRvB..73d1402B |issn=1098-0121}}</ref>
	Boron nitride has not been found in nature and therefore is produced synthetically. The most common raw materials for BN synthesis, boric acid and boron trioxide are produced on industrial scales by treating minerals ] and ] with ] or ]:
	:Na<sub>2</sub>B<sub>4</sub>O<sub>7</sub>·10H<sub>2</sub>O (borax) + H<sub>2</sub>SO<sub>4</sub> → 4 H<sub>3</sub>BO<sub>3</sub> (boric acid) + Na<sub>2</sub>SO<sub>4</sub> + 5 H<sub>2</sub>O
	Boron trioxide is obtained by heating boric acid.<ref>{{cite book|author=Pradyot Patnaik|year = 2003|title =Handbook of Inorganic Chemical Compounds|publisher = McGraw-Hill|page = 119| isbn =0070494398|url= http://books.google.com/?id=Xqj-TTzkvTEC&pg=PA119|accessdate = 2009-06-06}}</ref>
			The anisotropy of Young's modulus and ] depends on the system size.<ref>{{Cite journal |last1=Thomas |first1=Siby |last2=Ajith |first2=K M |last3=Valsakumar |first3=M C |date=2016-07-27 |title=Directional anisotropy, finite size effect and elastic properties of hexagonal boron nitride |url=https://iopscience.iop.org/article/10.1088/0953-8984/28/29/295302 |journal=Journal of Physics: Condensed Matter |volume=28 |issue=29 |pages=295302 |doi=10.1088/0953-8984/28/29/295302 |pmid=27255345 |bibcode=2016JPCM...28C5302T |issn=0953-8984}}</ref> h-BN also exhibits strongly anisotropic strength and ],<ref>{{Cite journal |last1=Ahmed |first1=Tousif |last2=Procak |first2=Allison |last3=Hao |first3=Tengyuan |last4=Hossain |first4=Zubaer M. |date=2019-04-17 |title=Strong anisotropy in strength and toughness in defective hexagonal boron nitride |url=https://link.aps.org/doi/10.1103/PhysRevB.99.134105 |journal=Physical Review B |language=en |volume=99 |issue=13 |page=134105 |doi=10.1103/PhysRevB.99.134105 |bibcode=2019PhRvB..99m4105A |issn=2469-9950}}</ref> and maintains these over a range of ]s, showing that the anisotropy is independent to the defect type.
			==Natural occurrence==
			In 2009, cubic form (c-BN) was reported in ], and the name ] proposed. The substance was found in dispersed ]-sized inclusions in chromium-rich rocks. In 2013, the International Mineralogical Association affirmed the mineral and the name.<ref>{{cite journal|author=Dobrzhinetskaya, L.F. |year=2013|title=Qingsongite, IMA 2013-030|journal=CNMNC Newsletter|volume=16|pages=2708|display-authors=etal}}</ref><ref>{{cite journal|author=Dobrzhinetskaya, L.F. |year=2014|title=Qingsongite, natural cubic boron nitride: The first boron mineral from the Earth's mantle|journal=American Mineralogist|volume=99|issue=4|pages=764–772|url=http://www.minsocam.org/msa/ammin/toc/Abstracts/2014_Abstracts/APR14_Abstracts/Dobr_p764_14.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.minsocam.org/msa/ammin/toc/Abstracts/2014_Abstracts/APR14_Abstracts/Dobr_p764_14.pdf |archive-date=2022-10-09 |url-status=live|doi=10.2138/am.2014.4714|display-authors=etal|bibcode=2014AmMin..99..764D|s2cid=130947756}}</ref><ref>{{Cite web|url=https://www.mindat.org/min-43792.html|title = Qingsongite}}</ref><ref>{{Cite web|url=https://www.ima-mineralogy.org/Minlist.htm|title=List of Minerals|date=21 March 2011}}</ref>
			==Synthesis==
	===Preparation and reactivity of hexagonal BN===		===Preparation and reactivity of hexagonal BN===
	Hexagonal boron nitride is obtained by the reacting boron trioxide (B<sub>2</sub>O<sub>3</sub>) or boric acid (B(OH)<sub>3</sub>) with ] (NH<sub>3</sub>) or ] (CO(NH<sub>2</sub>)<sub>2</sub>) in nitrogen atmosphere:<ref name=prod>{{cite journal| author= S. Rudolph| journal = American Ceramic Society Bulletin| volume = 79|year =2000| page = 50| url = http://www.a-m.de/deu/literatur/cb0600.html|title=Boron Nitride: Mineral Review 2000}}</ref>		Hexagonal boron nitride is obtained by the treating boron trioxide ({{chem2|B2O3}}) or boric acid ({{chem2|H3BO3}}) with ] ({{chem2|NH3}}) or ] ({{chem2|CO(NH2)2}}) in an inert atmosphere:<ref name=prod>{{cite journal | author = Rudolph, S. | journal = American Ceramic Society Bulletin | volume = 79 | year = 2000 | page = 50 | url = http://www.a-m.de/deu/literatur/cb0600.html | title = Boron Nitride (BN) | url-status = dead | archive-url = https://web.archive.org/web/20120306221940/http://www.a-m.de/deu/literatur/cb0600.html | archive-date = 2012-03-06}}</ref>
	:B<sub>2</sub>O<sub>3</sub> + 2 NH<sub>3</sub> → 2 BN + 3 H<sub>2</sub>O (T = 900&nbsp;°C)		:{{chem2|B2O3 + 2 NH3 → 2 BN + 3 H2O}} (''T'' = 900&nbsp;°C)
	:B(OH)<sub>3</sub> + NH<sub>3</sub> → BN + 3 H<sub>2</sub>O (T = 900&nbsp;°C)		:{{chem2|B(OH)3 + NH3 → BN + 3 H2O}} (''T'' = 900&nbsp;°C)
	:B<sub>2</sub>O<sub>3</sub> + CO(NH<sub>2</sub>)<sub>2</sub> → 2 BN + CO<sub>2</sub> + 2 H<sub>2</sub>O (T > 1000&nbsp;°C)		:{{chem2|B2O3 + CO(NH2)2 → 2 BN + CO2 + 2 H2O}} (''T'' > 1000&nbsp;°C)
	:B<sub>2</sub>O<sub>3</sub> + 3 CaB<sub>6</sub> + 10 N<sub>2</sub> → 20 BN + 3 CaO (T > 1500&nbsp;°C)		:{{chem2|B2O3 + 3 CaB6 + 10 N2 → 20 BN + 3 CaO}} (''T'' > 1500&nbsp;°C)
	The resulting disordered (]) boron nitride contains 92–95% BN and 5–8% B<sub>2</sub>O<sub>3</sub>. The remaining B<sub>2</sub>O<sub>3</sub> can be evaporated in a second step at temperatures >1500&nbsp;°C in order to achieve BN concentration >98%. Such annealing also crystallizes BN, the size of the crystallites increasing with the annealing temperature.<ref name=dkg/><ref>{{cite web|url =http://hubacek.jp/bn/bn.htm|accessdate=2009-06-06|title=Synthesis of Boron Nitride from Oxide Precursors|archiveurl = http://web.archive.org/web/20071212115253/http://hubacek.jp/bn/bn.htm |archivedate = December 12, 2007|deadurl=yes}}</ref>		The resulting disordered (]) material contains 92–95% BN and 5–8% {{chem2|B2O3}}. The remaining {{chem2|B2O3}} can be evaporated in a second step at temperatures {{nowrap|> 1500 °C}} in order to achieve BN concentration >98%. Such annealing also crystallizes BN, the size of the crystallites increasing with the annealing temperature.<ref name=dkg/><ref>{{cite web | url = http://hubacek.jp/bn/bn.htm | access-date = 2009-06-06 | title = Synthesis of Boron Nitride from Oxide Precursors | archive-url = https://web.archive.org/web/20071212115253/http://hubacek.jp/bn/bn.htm | archive-date = December 12, 2007 | url-status=dead}}</ref>
	h-BN parts can be fabricated inexpensively by hot-pressing with subsequent machining. The parts are made from boron nitride powders adding boron oxide for better compressibility. Thin films of boron nitride can be obtained by ] from ] and nitrogen precursors.<ref name=cvd>{{cite journal| title = Review of advances in cubic boron nitride film synthesis|author = P.B. Mirkarimi| journals= Materials Science and Engineering: R: Reports| volume = 21|year = 1997 |pages = 47–100| doi =10.1016/S0927-796X(97)00009-0| journal = Materials Science and Engineering R Reports| last2 = McCarty| first2 = K| last3 = Medlin| first3 = D| issue = 2}}</ref> Combustion of boron powder in nitrogen ] at 5500&nbsp;°C yields ] boron nitride used for lubricants and ]s.<ref>{{cite journal| author = Robert T. Paine, Chaitanya K. Narula| title = Synthetic routes to boron nitride| journal = Chem. Rev. |year = 1990 |volume = 90 |pages = 73–91| doi= 10.1021/cr00099a004}}</ref>		h-BN parts can be fabricated inexpensively by hot-pressing with subsequent machining. The parts are made from boron nitride powders adding boron oxide for better compressibility. Thin films of boron nitride can be obtained by ] from ] and nitrogen precursors.<ref name=cvd>{{cite journal | title = Review of Advances in Cubic Boron Nitride Film Synthesis | author = Mirkarimi, P. B. | volume = 21 | year = 1997 | pages = 47–100 | doi = 10.1016/S0927-796X(97)00009-0 | journal = Materials Science and Engineering: R: Reports | issue = 2 |display-authors=etal| url = https://zenodo.org/record/1260151}}</ref> ] also has developed boron nitride coatings that may be painted on a surface. Combustion of boron powder in nitrogen ] at 5500&nbsp;°C yields ] boron nitride used for lubricants and ]s.<ref>{{cite journal |author1=Paine, Robert T. |author2=Narula, Chaitanya K. | title = Synthetic Routes to Boron Nitride | journal = Chemical Reviews | year = 1990 | volume = 90 | pages = 73–91 | doi= 10.1021/cr00099a004}}</ref>
	Boron nitride reacts with ] in ] at −30&nbsp;°C to produce an extremely sensitive ], NI<sub>3</sub>, in low yield.<ref>{{cite journal |author = I. Tornieporth-Oetting and T. Klapötke|journal = Angewandte Chemie International Edition |year = 1990|volume = 29| pages =677–679| doi = 10.1002/anie.199006771 |title = Nitrogen Triiodide |issue = 6}}</ref>		Boron nitride reacts with ] to give {{chem2|NI3}} in low yield.<ref>{{cite journal |author1=Tornieporth-Oetting, I. |author2=Klapötke, T. | journal = Angewandte Chemie International Edition | year = 1990 | volume = 29 | pages =677–679 | doi = 10.1002/anie.199006771 | title = Nitrogen Triiodide | issue = 6}}</ref>
			Boron nitride reacts with nitrides of lithium, alkaline earth metals and lanthanides to form ]s.<ref name = "Housecroft2d">{{cite book |author1=Housecroft, Catherine E. |author2=Sharpe, Alan G. | year=2005 |title=Inorganic Chemistry|edition=2d |publisher=Pearson education|pages=318|isbn=978-0-13-039913-7}}</ref> For example:
			:{{chem2|Li3N + BN → Li3BN2}}
	===Intercalation of hexagonal BN===		===Intercalation of hexagonal BN===
	{{see also|Graphite intercalation compound}}		{{see also|Graphite intercalation compound|Graphene boron nitride nanohybrid materials}}
	]		]
	Similar to graphite, various molecules, such as NH<sub>3</sub><ref>{{cite journal| author = V. L. Solozhenko|journal = Phys. Chem. Chem. Phys.|year = 2002 |page = 5386| doi = 10.1039/b206005a| title =In situ studies of boron nitride crystallization from BN solutions in supercritical N–H fluid at high pressures and temperatures| volume = 4| last2 = Le Godec| first2 = Yann| last3 = Klotz| first3 = Stefan| last4 = Mezouar| first4 = Mohamed| last5 = Turkevich| first5 = Vladimir Z.| last6 = Besson| first6 = Jean-Michel| issue = 21}}</ref> or alkali metals,<ref>{{cite journal| author= G. L. Doll| title = Intercalation of hexagonal boron nitride with potassium |journal = J. Appl. Phys. |volume = 66 |page = 2554 |year = 1989 |doi =10.1063/1.344219| last2= Speck| first2= J. S.| last3= Dresselhaus| first3= G.| last4= Dresselhaus| first4= M. S.| last5= Nakamura| first5= K.| last6= Tanuma| first6= S.-I.| issue= 6}}</ref> can be intercalated into hexagonal boron nitride, that is inserted between its layers. Both experiment and theory suggest the intercalation is much more difficult for BN than for graphite.<ref>{{cite journal| author =Bai-Qing Dai and Gui-Ling Zhang|journal= Materials Chemistry and Physics| volume = 78|year =2003 |page = 304| doi = 10.1016/S0254-0584(02)00205-5| title =A DFT study of hBN compared with graphite in forming alkali metal intercalation compounds| issue =2}}</ref>		Various species intercalate into hexagonal BN, such as {{chem2|NH3}} intercalate<ref>{{cite journal | author = Solozhenko, V. L. | journal = Physical Chemistry Chemical Physics | year = 2002 | page = 5386 | doi = 10.1039/b206005a | title = ''In situ'' Studies of Boron Nitride Crystallization from BN Solutions in Supercritical N–H Fluid at High Pressures and Temperatures | volume = 4 | issue = 21 |bibcode = 2002PCCP....4.5386S |display-authors=etal}}</ref> or alkali metals.<ref>{{cite journal | author = Doll, G. L. | title = Intercalation of Hexagonal Boron Nitride with Potassium | journal = Journal of Applied Physics | volume = 66 | page = 2554 | year = 1989 | doi = 10.1063/1.344219 | issue = 6 |bibcode = 1989JAP....66.2554D |display-authors=etal}}</ref>
	===Preparation of cubic BN===		===Preparation of cubic BN===
	Synthesis of c-BN uses same methods as that of diamond: Cubic boron nitride is produced by treating hexagonal boron nitride at high pressure and temperature, much as ] is produced from graphite. Direct conversion of hexagonal boron nitride to the cubic form has been observed at pressures between 5 and 18 GPa and temperatures between 1730 and 3230&nbsp;°C, that is similar parameters as for direct graphite-diamond conversion.<ref name=wentorf>{{cite journal| author = R. H. Wentorf| title = Cubic form of boron nitride| journal = J. Chem. Phys.|volume = 26|page = 956|year = 1957|doi = 10.1063/1.1731679| issue = 3}}</ref> The addition of a small amount of boron oxide can lower the required pressure to 4–7 GPa and temperature to 1500&nbsp;°C. As in diamond synthesis, to further reduce the conversion pressures and temperatures, a catalyst is added, such as lithium, potassium, or magnesium, their nitrides, their fluoronitrides, water with ammonium compounds, or hydrazine.<ref name=vel>{{cite journal| doi=10.1016/0921-5107(91)90121-B |title = Cubic boron nitride: synthesis, physicochemical properties and applications| author = L. Vel|journal = Materials Science and Engineering: B| volume = 10|year = 1991|page = 149| last2=Demazeau| first2=G| last3=Etourneau| first3=J| issue=2}}</ref><ref>{{cite journal| author = O. Fukunaga| title = Science and technology in the recent development of boron nitride materials| year = 2002|journal = J. Phys.: Condens. Matter|volume = 14|page = 10979| doi= 10.1088/0953-8984/14/44/413| issue = 44}}</ref> Other industrial synthesis methods, again borrowed from diamond growth, use crystal growth in a temperature gradient, or explosive ]. The shock wave method is used to produce material called ], a superhard compound of boron, carbon, and nitrogen.<ref>{{cite journal| author = T. Komatsu| last2 = Samedima| first2 = Miho| last3 = Awano| first3 = Ternyuki| last4 = Kakadate| first4 = Yozo| last5 = Fujiwara| first5 = Syuzo|title = Creation of superhard B–C–N heterodiamond using an advanced shock wave compression technology|journal = Journal of Materials Processing Technology |volume = 85|year = 1999|page = 69| doi= 10.1016/S0924-0136(98)00263-5}}</ref>		c-BN is prepared analogously to the preparation of ] from graphite. Direct conversion of hexagonal boron nitride to the cubic form has been observed at pressures between 5 and 18&nbsp;GPa and temperatures between 1730 and 3230&nbsp;°C, that is similar parameters as for direct graphite-diamond conversion.<ref name=wentorf>{{cite journal | author = Wentorf, R. H. Jr. | author-link = Robert H. Wentorf, Jr. |date=March 1961 | title = Synthesis of the Cubic Form of Boron Nitride | journal = Journal of Chemical Physics | volume = 34 | issue = 3 | pages = 809–812 | doi = 10.1063/1.1731679 |bibcode = 1961JChPh..34..809W}}</ref> The addition of a small amount of boron oxide can lower the required pressure to 4–7&nbsp;GPa and temperature to 1500&nbsp;°C. As in diamond synthesis, to further reduce the conversion pressures and temperatures, a catalyst is added, such as lithium, potassium, or magnesium, their nitrides, their fluoronitrides, water with ammonium compounds, or hydrazine.<ref name=vel>{{cite journal | doi = 10.1016/0921-5107(91)90121-B | title = Cubic Boron Nitride: Synthesis, Physicochemical Properties and Applications | author = Vel, L. | journal = Materials Science and Engineering: B | volume = 10 | year = 1991 | page = 149 | issue = 2 |display-authors=etal}}</ref><ref>{{cite journal | author = Fukunaga, O. | title = Science and Technology in the Recent Development of Boron Nitride Materials | year = 2002 | journal = Journal of Physics: Condensed Matter | volume = 14 | page = 10979 | doi = 10.1088/0953-8984/14/44/413 | issue = 44 |bibcode = 2002JPCM...1410979F | s2cid = 250835481}}</ref> Other industrial synthesis methods, again borrowed from diamond growth, use crystal growth in a temperature gradient, or explosive ]. The shock wave method is used to produce material called ], a superhard compound of boron, carbon, and nitrogen.<ref>{{cite journal | author = Komatsu, T. | title = Creation of Superhard B–C–N Heterodiamond Using an Advanced Shock Wave Compression Technology | journal = Journal of Materials Processing Technology | volume = 85 | issue = 1–3 | year = 1999 | page = 69 | doi = 10.1016/S0924-0136(98)00263-5 |display-authors=etal}}</ref>
	Low-pressure deposition of thin films of cubic boron nitride is possible. As in diamond growth, the major problem is to suppress the growth of hexagonal phases (h-BN or graphite, respectively). Whereas in diamond growth this is achieved by adding hydrogen gas, ] is used for c-BN. ], ], ], ], and other ] methods are used as well.<ref name=cvd/>		Low-pressure deposition of thin films of cubic boron nitride is possible. As in diamond growth, the major problem is to suppress the growth of hexagonal phases (h-BN or graphite, respectively). Whereas in diamond growth this is achieved by adding hydrogen gas, ] is used for c-BN. ], ], ], ], and other ] methods are used as well.<ref name=cvd/>
	===Preparation of wurtzite BN===		===Preparation of wurtzite BN===
	Wurtzite BN can be obtained via static high-pressure or dynamic shock methods.<ref>{{cite journal| title = Characterization of wurtzite type boron nitride synthesized by shock compression|author = T. Soma|journal = Materials Research Bulletin| volume = 9|year = 1974 |page = 755| doi = 10.1016/0025-5408(74)90110-X| last2 = Sawaoka| first2 = A| last3 = Saito| first3 = S| issue = 6}}</ref> The limits of its stability are not well defined. Both c-BN and w-BN are formed by compressing h-BN, but formation of w-BN occurs at much lower temperatures close to 1700&nbsp;°C.<ref name=vel/>		Wurtzite BN can be obtained via static high-pressure or dynamic shock methods.<ref>{{cite journal | title = Characterization of Wurtzite Type Boron Nitride Synthesized by Shock Compression | author = Soma, T. | journal = Materials Research Bulletin | volume = 9 | year = 1974 | page = 755 | doi = 10.1016/0025-5408(74)90110-X | issue = 6 |display-authors=etal}}</ref> The limits of its stability are not well defined. Both c-BN and w-BN are formed by compressing h-BN, but formation of w-BN occurs at much lower temperatures close to 1700&nbsp;°C.<ref name=vel/>
	===Production statistics===		===Production statistics===
	Whereas the production and consumption figures for the raw materials used for BN synthesis, namely boric acid and boron trioxide, are well known (see ]), the corresponding numbers for the boron nitride are not listed in statistical reports. An estimate for the 1999 world production is 300 to 350 metric tons. The major producers and consumers of BN are located in the United States, Japan, China and Germany. In 2000, prices varied from about $75/kg to $120/kg for standard industrial-quality h-BN and were about up to $200–$400/kg for high purity BN grades.<ref name=prod/>		Whereas the production and consumption figures for the raw materials used for BN synthesis, namely boric acid and boron trioxide, are well known (see ]), the corresponding numbers for the boron nitride are not listed in statistical reports. An estimate for the 1999 world production is 300 to 350 ]. The major producers and consumers of BN are located in the United States, Japan, China and Germany. In 2000, prices varied from about $75–120/kg for standard industrial-quality h-BN and were about up to $200–400/kg for high purity BN grades.<ref name=prod/>
	==Applications==		==Applications==
	===Hexagonal BN===		===Hexagonal BN===
			{{Main|Synthesis of hexagonal boron nitride}}
	]		]
	Hexagonal BN is the most widely used polymorph. It is a good lubricant at both low and high temperatures (up to 900&nbsp;°C, even in an oxidizing atmosphere). h-BN lubricant is particularly useful when the electrical conductivity or chemical reactivity of graphite (alternative lubricant) would be problematic. Another advantage of h-BN over graphite is that its lubricity does not require water or gas molecules trapped between the layers. Therefore, h-BN lubricants can be used even in vacuum, e.g. in space applications. The lubricating properties of fine-grained h-BN are used in ], ]s, ]s, and ] leads.<ref name=b1>{{cite book| author = Jochen Greim, Karl A. Schwetz |title = Boron Carbide, Boron Nitride, and Metal Borides, in Ullmann's Encyclopedia of Industrial Chemistry |publisher = Wiley-VCH: Weinheim |year = 2005 |doi = 10.1002/14356007.a04_295.pub2}}</ref>		Hexagonal BN (h-BN) is the most widely used polymorph. It is a good lubricant at both low and high temperatures (up to 900&nbsp;°C, even in an oxidizing atmosphere). h-BN lubricant is particularly useful when the electrical conductivity or chemical reactivity of graphite (alternative lubricant) would be problematic. In internal combustion engines, where graphite could be oxidized and turn into carbon sludge, h-BN with its superior thermal stability can be added to engine lubricants. As with all nano-particle suspensions, Brownian-motion settlement is a problem. Settlement can clog engine oil filters, which limits solid lubricant applications in a combustion engine to automotive racing, where engine re-building is common. Since carbon has appreciable solubility in certain alloys (such as steels), which may lead to degradation of properties, BN is often superior for high temperature and/or high pressure applications. Another advantage of h-BN over graphite is that its lubricity does not require water or gas molecules trapped between the layers. Therefore, h-BN lubricants can be used in vacuum, such as space applications. The lubricating properties of fine-grained h-BN are used in ], ]s, ]s, and ] leads.<ref name=b1>{{cite book |author1=Greim, Jochen |author2=Schwetz, Karl A. | chapter = Boron Carbide, Boron Nitride, and Metal Borides | title = Ullmann's Encyclopedia of Industrial Chemistry | publisher = Wiley-VCH | location = Weinheim | year = 2005 | doi = 10.1002/14356007.a04_295.pub2 |isbn=978-3527306732}}</ref>
			Hexagonal BN was first used in cosmetics around 1940 in ]. Because of its high price, h-BN was abandoned for this application. Its use was revitalized in the late 1990s with the optimization h-BN production processes, and currently h-BN is used by nearly all leading producers of cosmetic products for ], ], ]s, blushers, ], ]s and other skincare products.<ref name=dkg/>
			Because of its excellent thermal and chemical stability, boron nitride ceramics and coatings are used high-temperature equipment. h-BN can be included in ceramics, alloys, resins, plastics, rubbers, and other materials, giving them self-lubricating properties. Such materials are suitable for construction of e.g. ] and in steelmaking.<ref name=dkg/> Many quantum devices use multilayer h-BN as a substrate material. It can also be used as a dielectric in resistive random access memories.<ref>{{Cite journal|last1=Pan|first1=Chengbin|last2=Ji|first2=Yanfeng|last3=Xiao|first3=Na|last4=Hui|first4=Fei|last5=Tang|first5=Kechao|last6=Guo|first6=Yuzheng|last7=Xie|first7=Xiaoming|last8=Puglisi|first8=Francesco M.|last9=Larcher|first9=Luca|date=2017-01-01|title=Coexistence of Grain-Boundaries-Assisted Bipolar and Threshold Resistive Switching in Multilayer Hexagonal Boron Nitride|journal=Advanced Functional Materials|volume=27|issue=10|pages=1604811|doi=10.1002/adfm.201604811|hdl=11380/1129421|s2cid=100500198 |hdl-access=free}}</ref><ref>{{Cite book|last1=Puglisi|first1=F. M.|last2=Larcher|first2=L.|last3=Pan|first3=C.|last4=Xiao|first4=N.|last5=Shi|first5=Y.|last6=Hui|first6=F.|last7=Lanza|first7=M.|title=2016 IEEE International Electron Devices Meeting (IEDM) |chapter=2D h-BN based RRAM devices |date=2016-12-01|pages=34.8.1–34.8.4|doi=10.1109/IEDM.2016.7838544|isbn=978-1-5090-3902-9|s2cid=28059875}}</ref>
			Hexagonal BN is used in ] and ]s as a charge leakage barrier layer of the photo drum.<ref>{{cite journal | author = Schein, L. B. | title = Electrophotography and Development Physics | journal = Physics Today | series = Springer Series in Electrophysics | volume = 14 | issue = 12 | pages = 66–68 |publisher = Springer-Verlag | location = Berlin | year = 1988 | isbn = 9780387189024 | bibcode = 1989PhT....42l..66S | doi = 10.1063/1.2811250}}</ref> In the automotive industry, h-BN mixed with a binder (boron oxide) is used for sealing ]s, which provide feedback for adjusting fuel flow. The binder utilizes the unique temperature stability and insulating properties of h-BN.<ref name=dkg/>
			Parts can be made by ] from four commercial grades of h-BN. Grade HBN contains a ] ]; it is usable up to 550–850&nbsp;°C in oxidizing atmosphere and up to 1600&nbsp;°C in vacuum, but due to the boron oxide content is sensitive to water. Grade HBR uses a ] binder and is usable at 1600&nbsp;°C. Grades HBC and HBT contain no binder and can be used up to 3000&nbsp;°C.<ref>{{cite book | author = Harper, Charles A. | title = Handbook of Ceramics, Glasses and Diamonds | publisher = McGraw-Hill | year = 2001 | isbn = 978-0070267121}}</ref>
			]s (h-BN) can be deposited by catalytic decomposition of ] at a temperature ~1100&nbsp;°C in a ] setup, over areas up to about 10&nbsp;cm<sup>2</sup>. Owing to their hexagonal atomic structure, small lattice mismatch with graphene (~2%), and high uniformity they are used as substrates for graphene-based devices.<ref name=nn>{{cite journal|doi=10.1021/nn503140y|pmid=25094030|title=Large-Area Monolayer Hexagonal Boron Nitride on Pt Foil|journal=ACS Nano|volume=8|issue=8|pages=8520–8|year=2014|last1=Park|first1=Ji-Hoon|last2=Park|first2=Jin Cheol|last3=Yun|first3=Seok Joon|last4=Kim|first4=Hyun|last5=Luong|first5=Dinh Hoa|last6=Kim|first6=Soo Min|last7=Choi|first7=Soo Ho|last8=Yang|first8=Woochul|last9=Kong|first9=Jing|last10=Kim|first10=Ki Kang|last11=Lee|first11=Young Hee}}</ref> BN nanosheets are also excellent ]s. Their high proton transport rate, combined with the high electrical resistance, may lead to applications in ] and ].<ref>{{cite journal | author = Hu, S. |display-authors=etal | title = Proton transport through one-atom-thick crystals | journal = Nature | year = 2014 | volume = 516 | issue = 7530 | pages = 227–230 | doi = 10.1038/nature14015|pmid=25470058 |arxiv = 1410.8724 |bibcode = 2014Natur.516..227H |s2cid=4455321}}</ref>
			h-BN has been used since the mid-2000s as a bullet and bore lubricant in precision target rifle applications as an alternative to ] coating, commonly referred to as "moly". It is claimed to increase effective barrel life, increase intervals between bore cleaning and decrease the deviation in point of impact between clean bore first shots and subsequent shots.<ref>{{cite web | url = http://bulletin.accurateshooter.com/2014/09/hexagonal-boron-nitride-hbn-how-well-does-it-work/ | title = Hexagonal Boron Nitride (HBN)—How Well Does It Work? | author = <!--Staff writer(s); no by-line.--> | date = 8 September 2014 | website = AccurateShooter.com | access-date = 28 December 2015}}</ref>
			h-BN is used as a release agent in molten metal and glass applications. For example, ] developed and currently produces a line of paintable h-BN coatings that are used by manufacturers of molten aluminium, non-ferrous metal, and glass.<ref>{{Cite web|url=http://www.colourdeverre.com/img/projects/advancedpriming.pdf|title=colourdeverre.com/img/projects/advancedpriming.pdf}}</ref> Because h-BN is nonwetting and lubricious to these molten materials, the coated surface (i.e. mold or crucible) does not stick to the material.<ref>{{Cite web|url=https://www.researchgate.net/publication/234787198|title=Wettability, Spreading, and Interfacial Phenomena in High-Temperature Coatings}}</ref><ref>{{Cite web|url=https://hal.science/hal-02113581/document|title=Substrate Release Mechanisms for Gas Metal Arc 3-D Aluminum Metal Printing. 3D Printing &Additive Manufacturing}}</ref><ref>{{Cite web|url=https://www.researchgate.net/publication/265172365|title=Wear properties of squeeze cast in situ Mg2Si–A380 alloy}}</ref><ref>{{Cite web|url=http://www.jwri.osaka-u.ac.jp/~dpt9/Acta(1993)BNAl.pdf|title=INTERFACIAL REACTION WETTING IN THE BORON NITRIDE/MOLTEN ALUMINUM SYSTEM}}</ref>
			===Cubic BN===
			Cubic boron nitride (CBN or c-BN) is widely used as an ].<ref name="mprg">{{Cite book | vauthors = Todd RH, Allen DK, Dell KAlting L | year = 1994 | title = Manufacturing Processes Reference Guide | publisher = Industrial Press Inc. | pages = 43–48 | url = https://books.google.com/books?id=6x1smAf_PAcC | isbn = 978-0-8311-3049-7}}</ref> Its usefulness arises from its insolubility in ], ], and related ]s at high temperatures, whereas diamond is soluble in these metals. Polycrystalline c-BN ('''PCBN''') abrasives are therefore used for machining steel, whereas diamond abrasives are preferred for aluminum alloys, ceramics, and stone. When in contact with oxygen at high temperatures, BN forms a ] of boron oxide. Boron nitride binds well with metals due to formation of interlayers of metal borides or nitrides. Materials with cubic boron nitride crystals are often used in the ]s of ]s. For grinding applications, softer binders such as resin, porous ceramics and soft metals are used. Ceramic binders can be used as well. Commercial products are known under names "]" (by Hyperion Materials & Technologies<ref>{{cite web |title=Diamond and Cubic Boron Nitride (CBN) Abrasives |url=https://www.hyperionmt.com/products/Abrasives/mesh-cbn |website=Hyperion Materials & Technologies |access-date=21 June 2022}}</ref>), and "Elbor" or "Cubonite" (by Russian vendors).<ref name=b1/>
			Contrary to diamond, large c-BN pellets can be produced in a simple process (called sintering) of annealing c-BN powders in nitrogen flow at temperatures slightly below the BN decomposition temperature. This ability of c-BN and h-BN powders to fuse allows cheap production of large BN parts.<ref name=b1/>
			Similar to diamond, the combination in c-BN of highest thermal conductivity and electrical resistivity is ideal for ]s.
			As cubic boron nitride consists of light atoms and is very robust chemically and mechanically, it is one of the popular materials for X-ray membranes: low mass results in small X-ray absorption, and good mechanical properties allow usage of thin membranes, further reducing the absorption.<ref>{{cite journal |author1=El Khakani, M. A. |author2=Chaker, M. | title = Physical Properties of the X-Ray Membrane Materials | journal = Journal of Vacuum Science and Technology B | volume = 11 | pages = 2930–2937 | year = 1993 | doi = 10.1116/1.586563 | issue = 6 |bibcode = 1993JVSTB..11.2930E}}</ref>
			===Amorphous BN===
	Hexagonal BN was first used in cosmetics around 1940 in ]. However, because of its high price, h-BN was soon abandoned for this application. Its use was revitalized in the late 1990s with the optimization h-BN production processes, and currently h-BN is used by nearly all leading producers of cosmetic products for ], ], ]s, blushers, ], ]s and other skincare products.<ref name=dkg/>
			Layers of amorphous boron nitride (a-BN) are used in some ]s, e.g. ]s. They can be prepared by chemical decomposition of ]] with ], or by thermal chemical vapor deposition methods. Thermal CVD can be also used for deposition of h-BN layers, or at high temperatures, c-BN.<ref>{{cite journal | author = Schmolla, W. | title = Positive Drift Effect of BN-InP Enhancement N-Channel MISFET | doi =10.1080/00207218508939000 | journal = International Journal of Electronics | volume = 58 | year = 1985 | page = 35}}</ref>
			==Other forms of boron nitride==
	Because of its excellent thermal and chemical stability, boron nitride ceramics are traditionally used as parts of high-temperature equipment. h-BN can be included in ceramics, alloys, resins, plastics, rubbers, and other materials, giving them self-lubricating properties. Such materials are suitable for construction of e.g. ] and in steelmaking.<ref name=dkg/> Plastics filled with BN have less thermal expansion as well as higher thermal conductivity and electrical resistivity. Due to its excellent dielectric and thermal properties, BN is used in electronics e.g. as a substrate for semiconductors, microwave-transparent windows, and as a structural material for seals.<ref>{{cite journal| author= R.F. Davis| title = III-V nitrides for electronic and optoelectronic applications| journal = Proceedings of the IEEE| year = 1991| volume= 79| pages = 702–712| doi = 10.1109/5.90133| issue= 5}}</ref>
			=== Atomically thin boron nitride ===
			{{Main|Boron nitride nanosheet}}
			Hexagonal boron nitride can be exfoliated to mono or few atomic layer sheets. Due to its analogous structure to that of graphene, atomically thin boron nitride is sometimes called ''white graphene''.<ref name="LiChen2016">{{cite journal|last1=Li|first1=Lu Hua|last2=Chen|first2=Ying|title=Atomically Thin Boron Nitride: Unique Properties and Applications|journal=Advanced Functional Materials|volume=26|issue=16|year=2016|pages=2594–2608|doi=10.1002/adfm.201504606|arxiv=1605.01136|bibcode=2016arXiv160501136L|s2cid=102038593}}</ref>
			====Mechanical properties====
	Hexagonal BN is used in ] and ]s as a charge leakage barrier layer of the photo drum.<ref>{{cite book| author = L.B. Schein|title = Electrophotography and Development Physics, Springer Series in Electrophysics|volume = 14|publisher = Springer-Verlag, Berlin |year = 1988}}</ref> In the automotive industry, h-BN mixed with a binder (boron oxide) is used for sealing ]s, which provide feedback for adjusting fuel flow. The binder utilizes the unique temperature stability and insulating properties of h-BN.<ref name=dkg/>
			Atomically thin boron nitride is one of the strongest electrically insulating materials. Monolayer boron nitride has an average Young's modulus of 0.865TPa and fracture strength of 70.5GPa, and in contrast to graphene, whose strength decreases dramatically with increased thickness, few-layer boron nitride sheets have a strength similar to that of monolayer boron nitride.<ref>{{Cite journal|last1=Falin|first1=Aleksey|last2=Cai|first2=Qiran|last3=Santos|first3=Elton J.G.|last4=Scullion|first4=Declan|last5=Qian|first5=Dong|last6=Zhang|first6=Rui|last7=Yang|first7=Zhi|last8=Huang|first8=Shaoming|last9=Watanabe|first9=Kenji|date=2017-06-22|title=Mechanical properties of atomically thin boron nitride and the role of interlayer interactions|journal=Nature Communications|volume=8|pages=15815|doi=10.1038/ncomms15815|pmid=28639613|pmc=5489686|arxiv=2008.01657|bibcode=2017NatCo...815815F}}</ref>
			====Thermal conductivity====
	Parts can be made of h-BN by ]. ] produces three grades of BN. HBN, with boron oxide ], usable to 550–850&nbsp;°C in oxidizing atmosphere and up to 1600 °C in vacuum, but due to the boron oxide content is sensitive to water. HBR uses ] binder and is usable at 1600&nbsp;°C. HBC grade uses no binder and can be used to 3000&nbsp;°C.<ref>{{cite book|author = Charles A. Harper| title = Handbook of ceramics, glasses and diamonds|publisher = McGraw-Hill|year = 2001|isbn = 007026712X}}</ref>
			Atomically thin boron nitride has one of the highest thermal conductivity coefficients (751 W/mK at room temperature) among semiconductors and electrical insulators, and its thermal conductivity increases with reduced thickness due to less intra-layer coupling.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Scullion|first2=Declan|last3=Gan|first3=Wei|last4=Falin|first4=Alexey|last5=Zhang|first5=Shunying|last6=Watanabe|first6=Kenji|last7=Taniguchi|first7=Takashi|last8=Chen|first8=Ying|last9=Santos|first9=Elton J. G.|date=2019|title=High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion|journal=Science Advances|language=en|volume=5|issue=6|pages=eaav0129|doi=10.1126/sciadv.aav0129|issn=2375-2548|pmc=6555632|pmid=31187056|arxiv=1903.08862|bibcode=2019SciA....5..129C}}</ref>
	===Cubic boron nitride===		====Thermal stability====
			The air stability of graphene shows a clear thickness dependence: monolayer graphene is reactive to oxygen at 250&nbsp;°C, strongly doped at 300&nbsp;°C, and etched at 450&nbsp;°C; in contrast, bulk graphite is not oxidized until 800&nbsp;°C.<ref name="LiSantos2014"/> Atomically thin boron nitride has much better oxidation resistance than graphene. Monolayer boron nitride is not oxidized till 700&nbsp;°C and can sustain up to 850&nbsp;°C in air; bilayer and trilayer boron nitride nanosheets have slightly higher oxidation starting temperatures.<ref name="LiCervenka2014">{{cite journal|last1=Li|first1=Lu Hua|last2=Cervenka|first2=Jiri|last3=Watanabe|first3=Kenji|last4=Taniguchi|first4=Takashi|last5=Chen|first5=Ying|title=Strong Oxidation Resistance of Atomically Thin Boron Nitride Nanosheets|journal=ACS Nano|volume=8|issue=2|year=2014|pages=1457–1462|doi=10.1021/nn500059s|pmid=24400990|arxiv=1403.1002|bibcode=2014arXiv1403.1002L|s2cid=5372545}}</ref> The excellent thermal stability, high impermeability to gas and liquid, and electrical insulation make atomically thin boron nitride potential coating materials for preventing surface oxidation and corrosion of metals<ref name="LiXing2014">{{cite journal|last1=Li|first1=Lu Hua|last2=Xing|first2=Tan|last3=Chen|first3=Ying|last4=Jones|first4=Rob|title=Nanosheets: Boron Nitride Nanosheets for Metal Protection (Adv. Mater. Interfaces 8/2014)|journal=Advanced Materials Interfaces|volume=1|issue=8|year=2014|pages=n/a|doi=10.1002/admi.201470047|doi-access=free}}</ref><ref>{{Cite journal|last1=Liu|first1=Zheng|last2=Gong|first2=Yongji|last3=Zhou|first3=Wu|last4=Ma|first4=Lulu|last5=Yu|first5=Jingjiang|last6=Idrobo|first6=Juan Carlos|last7=Jung|first7=Jeil|last8=MacDonald|first8=Allan H.|last9=Vajtai|first9=Robert|date=2013-10-04|title=Ultrathin high-temperature oxidation-resistant coatings of hexagonal boron nitride|journal=Nature Communications|volume=4|issue=1|pages=2541|doi=10.1038/ncomms3541|pmid=24092019|bibcode=2013NatCo...4.2541L|doi-access=free}}</ref> and other two-dimensional (2D) materials, such as ].<ref>{{Cite journal|last1=Chen|first1=Xiaolong|last2=Wu|first2=Yingying|last3=Wu|first3=Zefei|last4=Han|first4=Yu|last5=Xu|first5=Shuigang|last6=Wang|first6=Lin|last7=Ye|first7=Weiguang|last8=Han|first8=Tianyi|last9=He|first9=Yuheng|date=2015-06-23|title=High-quality sandwiched black phosphorus heterostructure and its quantum oscillations|journal=Nature Communications|volume=6|issue=1|pages=7315|doi=10.1038/ncomms8315|pmid=26099721|pmc=4557360|arxiv=1412.1357|bibcode=2015NatCo...6.7315C}}</ref>
	Cubic boron nitride (CBN or c-BN) is widely used as an ].<ref name="mprg">{{Cite book|first1 = Robert H.|last1 = Todd|first2 = Dell K.|last2 = Allen|first3 = Leo|last3 = Alting|year = 1994|title = Manufacturing Processes Reference Guide|publisher = Industrial Press Inc.|pages = 43–48|url = http://books.google.com/?id=6x1smAf_PAcC|isbn = 0-8311-3049-0|postscript =.}}</ref> Its usefulness arises from its insolubility in ], ], and related ] at high temperatures, whereas diamond is soluble in these metals to give carbides. Polycrystalline c-BN (PCBN) abrasives are therefore used for machining steel, whereas diamond abrasives are preferred for aluminum alloys, ceramics, and stone. When in contact with oxygen at high temperatures, BN forms a passivation layer of boron oxide. Boron nitride binds well with metals, due to formation of interlayers of metal borides or nitrides. Materials with cubic boron nitride crystals are often used in the ]s of ]s. For grinding applications, softer binders, e.g. resin, porous ceramics, and soft metals, are used. Ceramic binders can be used as well. Commercial products are known under names "]" (by Diamond Innovations), and "Elbor" or "Cubonite" (by Russian vendors). Similar to diamond, the combination in c-BN of highest thermal conductivity and electrical resistivity is ideal for heat spreaders. Contrary to diamond, large c-BN pellets can be produced in a simple process (called sintering) of annealing c-BN powders in nitrogen flow at temperatures slightly below the BN decomposition temperature. This ability of c-BN and h-BN powders to fuse allows cheap production of large BN parts.<ref name=b1/>
			====Better surface adsorption====
	As cubic boron nitride consists of light atoms and is very robust chemically and mechanically, it is one of the popular materials for X-ray membranes: low mass results in small X-ray absorption, and good mechanical properties allow usage of thin membranes, thus further reducing the absorption.<ref>{{cite journal| author = M. A. El Khakani and M. Chaker
			Atomically thin boron nitride has been found to have better surface adsorption capabilities than bulk hexagonal boron nitride.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Du|first2=Aijun|last3=Gao|first3=Guoping|last4=Mateti|first4=Srikanth|last5=Cowie|first5=Bruce C. C.|last6=Qian|first6=Dong|last7=Zhang|first7=Shuang|last8=Lu|first8=Yuerui|last9=Fu|first9=Lan|date=2016-08-29|title=Molecule-Induced Conformational Change in Boron Nitride Nanosheets with Enhanced Surface Adsorption|journal=Advanced Functional Materials|volume=26|issue=45|pages=8202–8210|doi=10.1002/adfm.201603160|arxiv=1612.02883|bibcode=2016arXiv161202883C|s2cid=13800939}}</ref> According to theoretical and experimental studies, atomically thin boron nitride as an adsorbent experiences conformational changes upon surface adsorption of molecules, increasing adsorption energy and efficiency. The synergic effect of the atomic thickness, high flexibility, stronger surface adsorption capability, electrical insulation, impermeability, high thermal and chemical stability of BN nanosheets can increase the ] by up to two orders, and in the meantime attain long-term stability and reusability not readily achievable by other materials.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Mateti|first2=Srikanth|last3=Yang|first3=Wenrong|last4=Jones|first4=Rob|last5=Watanabe|first5=Kenji|last6=Taniguchi|first6=Takashi|last7=Huang|first7=Shaoming|last8=Chen|first8=Ying|last9=Li|first9=Lu Hua|date=2016-05-20|title=Inside Back Cover: Boron Nitride Nanosheets Improve Sensitivity and Reusability of Surface-Enhanced Raman Spectroscopy (Angew. Chem. Int. Ed. 29/2016)|journal=Angewandte Chemie International Edition|volume=55|issue=29|pages=8457|doi=10.1002/anie.201604295|doi-access=free|hdl=10536/DRO/DU:30086239|hdl-access=free}}</ref><ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Mateti|first2=Srikanth|last3=Watanabe|first3=Kenji|last4=Taniguchi|first4=Takashi|last5=Huang|first5=Shaoming|last6=Chen|first6=Ying|last7=Li|first7=Lu Hua|date=2016-06-14|title=Boron Nitride Nanosheet-Veiled Gold Nanoparticles for Surface-Enhanced Raman Scattering|journal=ACS Applied Materials & Interfaces|volume=8|issue=24|pages=15630–15636|doi=10.1021/acsami.6b04320|pmid=27254250|arxiv=1606.07183|bibcode=2016arXiv160607183C|s2cid=206424168}}</ref>
	| title = Physical properties of the x-ray membrane materials| journal = J. Vac. Sci. Technol. B |volume = 11|page = 2930| year = 1993| doi = 10.1116/1.586563| issue = 6}}</ref>
	===Amorphous boron nitride===		====Dielectric properties====
			Atomically thin hexagonal boron nitride is an excellent dielectric substrate for graphene, molybdenum disulfide ({{chem2|MoS2}}), and many other 2D material-based electronic and photonic devices. As shown by electric force microscopy (EFM) studies, the electric field screening in atomically thin boron nitride shows a weak dependence on thickness, which is in line with the smooth decay of electric field inside few-layer boron nitride revealed by the first-principles calculations.<ref name="LiSantos2014">{{Cite journal|last1=Li|first1=Lu Hua|last2=Santos|first2=Elton J. G.|last3=Xing|first3=Tan|last4=Cappelluti|first4=Emmanuele|last5=Roldán|first5=Rafael|last6=Chen|first6=Ying|last7=Watanabe|first7=Kenji|last8=Taniguchi|first8=Takashi|year=2015|title=Dielectric Screening in Atomically Thin Boron Nitride Nanosheets|journal=Nano Letters|volume=15|issue=1|pages=218–223|doi=10.1021/nl503411a|pmid=25457561|arxiv=1503.00380|bibcode=2015NanoL..15..218L|s2cid=207677623}}</ref>
	Layers of amorphous boron nitride (a-BN) are used in some ], e.g. ]s. They can be prepared by chemical decomposition of ] with ], or by thermal chemical vapor deposition methods. Thermal CVD can be also used for deposition of h-BN layers, or at high temperatures, c-BN.<ref>{{cite journal| author= W. Schmolla|title = Positive drift effect of BN-InP enhancement n-channel MISFET| doi =10.1080/00207218508939000 |journal =International Journal of Electronics |volume =58 |year =1985 |page = 35}}</ref>
			====Raman characteristics====
	==Other BN forms==
			Raman spectroscopy has been a useful tool to study a variety of 2D materials, and the Raman signature of high-quality atomically thin boron nitride was first reported by Gorbachev et al. in 2011.<ref>{{Cite journal|last1=Gorbachev|first1=Roman V.|last2=Riaz|first2=Ibtsam|last3=Nair|first3=Rahul R.|last4=Jalil|first4=Rashid|last5=Britnell|first5=Liam|last6=Belle|first6=Branson D.|last7=Hill|first7=Ernie W.|last8=Novoselov|first8=Kostya S.|last9=Watanabe|first9=Kenji|date=2011-01-07|title=Hunting for Monolayer Boron Nitride: Optical and Raman Signatures|journal=Small|volume=7|issue=4|pages=465–468|doi=10.1002/smll.201001628|pmid=21360804|arxiv=1008.2868|s2cid=17344540}}</ref> and Li et al.<ref name="LiCervenka2014"/> However, the two reported Raman results of monolayer boron nitride did not agree with each other. Cai et al., therefore, conducted systematic experimental and theoretical studies to reveal the intrinsic Raman spectrum of atomically thin boron nitride.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Scullion|first2=Declan|last3=Falin|first3=Aleksey|last4=Watanabe|first4=Kenji|last5=Taniguchi|first5=Takashi|last6=Chen|first6=Ying|last7=Santos|first7=Elton J. G.|last8=Li|first8=Lu Hua|date=2017|title=Raman signature and phonon dispersion of atomically thin boron nitride|journal=Nanoscale|volume=9|issue=9|pages=3059–3067|doi=10.1039/c6nr09312d|pmid=28191567|url=https://pure.qub.ac.uk/portal/en/publications/raman-signature-and-phonon-dispersion-of-atomically-thin-boron-nitride(5f58d958-22ab-450f-97fb-cd7c0f25f5b4).html|arxiv=2008.01656|s2cid=206046676}}</ref> It reveals that atomically thin boron nitride without interaction with a substrate has a G band frequency similar to that of bulk hexagonal boron nitride, but strain induced by the substrate can cause Raman shifts. Nevertheless, the Raman intensity of G band of atomically thin boron nitride can be used to estimate layer thickness and sample quality.]. The center of each ring corresponds to the center of the pores]]
	===Boron nitride fibers===
			] by BN aerogel. Cyclohexane is stained with ] red dye and is floating on water. Bottom: reuse of the aerogel after burning in air.<ref name=nat>{{cite journal|doi=10.1038/srep10337|pmid=25976019|title=Ultralight boron nitride aerogels via template-assisted chemical vapor deposition|journal=Scientific Reports|volume=5|pages=10337|year=2015|last1=Song|first1=Yangxi|last2=Li|first2=Bin|last3=Yang|first3=Siwei|last4=Ding|first4=Guqiao|last5=Zhang|first5=Changrui|last6=Xie|first6=Xiaoming|pmc=4432566|bibcode=2015NatSR...510337S}}</ref>]]
	Hexagonal BN can be prepared in the form of fibers, structurally similar to ]s, by thermal decomposition of extruded ] (B<sub>3</sub>N<sub>3</sub>H<sub>6</sub>) fibers with addition of boron oxide in a nitrogen atmosphere at 1800&nbsp;°C. An alternative method is thermal decomposition of ] fibers impregnated with boric acid or ] in an atmosphere of ammonia and nitrogen above 1000&nbsp;°C. Boron nitride fibers are used as reinforcement in ]s, with the matrix materials ranging from organic resins to ceramics to metals (see ]).<ref>{{cite journal| author = T. S. Bartnitskaya| title = Preparation of boron nitride fibers with the use of hydrated cellulose. I. Decomposition of hydrated cellulose impregnated with boron-containing compounds|journal = Powder Metallurgy and Metal Ceramics| volume = 38 |year = 1999| page = 152| doi = 10.1007/BF02676041| last2 = Ostrovskaya| first2 = N. F.| last3 = Ul'yanova| first3 = T. M.| last4 = Fenochka| first4 = B. V.| issue = 3–4}}</ref>
	===Boron nitride nanomesh===		===Boron nitride nanomesh===
			{{Main|Nanomesh}}
	]
			] is a nanostructured two-dimensional material. It consists of a single BN layer, which forms by ] a highly regular mesh after high-temperature exposure of a clean ]<ref name="corso04">{{cite journal | author = Corso, M. | title = Boron Nitride Nanomesh | journal = Science | volume = 303 | pages = 217–220 | doi = 10.1126/science.1091979 | year = 2004 | pmid = 14716010 | issue = 5655 |bibcode = 2004Sci...303..217C | s2cid = 11964344 |display-authors=etal}}</ref> or ]<ref name="goriachko07">{{cite journal | author = Goriachko, A. | title = Self-Assembly of a Hexagonal Boron Nitride Nanomesh on Ru(0001) | journal = Langmuir | volume = 23 | issue = 6 | pages = 2928–2931 | doi = 10.1021/la062990t | pmid = 17286422 | year = 2007 |display-authors=etal}}</ref> surface to ] under ]. The nanomesh looks like an assembly of hexagonal pores. The distance between two pore centers is 3.2&nbsp;nm and the pore diameter is ~2&nbsp;nm. Other terms for this material are boronitrene or white graphene.<ref> {{Webarchive|url=https://web.archive.org/web/20180528042221/http://jacobs.physik.uni-saarland.de/forschung/Graphene.htm |date=2018-05-28}}. physik.uni-saarland.de</ref>
	]. The center of each ring corresponds to the center of the pores]]
			The boron nitride nanomesh is air-stable<ref name="bunk07">{{cite journal | author = Bunk, O. | title = Surface X-Ray Diffraction Study of Boron-Nitride Nanomesh in Air | journal = Surface Science | volume = 601 | pages = L7–L10 | doi = 10.1016/j.susc.2006.11.018 | year = 2007 | issue = 2 |bibcode = 2007SurSc.601L...7B | url = https://www.dora.lib4ri.ch/psi/islandora/object/psi%3A18158 |display-authors=etal}}</ref> and compatible with some liquids.<ref name="berner07">{{cite journal | author = Berner, S. | title = Boron Nitride Nanomesh: Functionality from a Corrugated Monolayer | journal = Angewandte Chemie International Edition | volume = 46 | issue = 27 | pages = 5115–5119 | doi = 10.1002/anie.200700234 | pmid = 17538919 | year = 2007 |display-authors=etal}}</ref><ref name="widmer07">{{cite journal | author = Widmer, R. | title = Electrolytic ''in situ'' STM Investigation of h-BN-Nanomesh |url=http://webmail.physik.unizh.ch/groups/osterwalder/zz_publications_old/EC_Widmer.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://webmail.physik.unizh.ch/groups/osterwalder/zz_publications_old/EC_Widmer.pdf |archive-date=2022-10-09 |url-status=live| journal = Electrochemical Communications | volume = 9 | pages = 2484–2488 | doi = 10.1016/j.elecom.2007.07.019 | year = 2007 | issue = 10 |display-authors=etal}}</ref> up to temperatures of 800&nbsp;°C.<ref name="corso04"/>
	{{main|Nanomesh}}
	] is an ] nanostructured two-dimensional material. It consists of a single BN layer, which forms by ] a highly regular mesh after high-temperature exposure of a clean ]<ref name="corso04">{{cite journal|author = M. Corso|title = Boron Nitride Nanomesh|journal=Science|volume = 303 |pages = 217–220 |doi = 10.1126/science.1091979|year = 2004|pmid = 14716010|last2 = Auwärter|first2 = W|last3 = Muntwiler|first3 = M|last4 = Tamai|first4 = A|last5 = Greber|first5 = T|last6 = Osterwalder|first6 = J|issue = 5655}}</ref> or ]<ref name="goriachko07">{{cite journal|author = A. Goriachko|title = Self-assembly of a hexagonal boron nitride nanomesh on Ru(0001)| journal=Langmuir Lett.|volume = 23|issue = 6 |pages = 2928–2931 |doi = 10.1021/la062990t|pmid = 17286422|year = 2007|last2 = He|first2 = Y|last3 = Knapp|first3 = Marcus|last4 = Over|first4 = Herbert|last5 = Corso|first5 = Martina|last6 = Brugger|first6 = Thomas|last7 = Berner|first7 = Simon|last8 = Osterwalder|first8 = Juerg|last9 = Greber|first9 = Thomas}}</ref> surface to borazine under ]. The nanomesh looks like an assembly of hexagonal pores. The distance between 2 pore centers is 3.2&nbsp;nm and the pore diameter is ~2&nbsp;nm.
			] and BN nanotube buckypaper.<ref name="BNpaper">{{cite journal|doi=10.1039/C5RA02988K |title=Polymer nanocomposites from free-standing, macroscopic boron nitride nanotube assemblies |journal=RSC Adv |volume=5 |issue=51 |pages=41186 |year=2015 |last1=Kim |first1=Keun Su |last2=Jakubinek |first2=Michael B. |last3=Martinez-Rubi |first3=Yadienka |last4=Ashrafi |first4=Behnam |last5=Guan |first5=Jingwen |last6=O'Neill |first6=K. |last7=Plunkett |first7=Mark |last8=Hrdina |first8=Amy |last9=Lin |first9=Shuqiong |last10=Dénommée |first10=Stéphane |last11=Kingston |first11=Christopher |last12=Simard |first12=Benoit |bibcode=2015RSCAd...541186K}}</ref>]]
	The boron nitride nanomesh is not only stable to decomposition under vacuum,<ref name="corso04"/> air<ref name="bunk07">{{cite journal|author = O. Bunk|title = Surface X-ray diffraction study of boron-nitride nanomesh in air|journal=Surf. Sci.|volume = 601 |pages = L7–L10 |doi = 10.1016/j.susc.2006.11.018| year = 2007|last2 = Corso|first2 = M|last3 = Martoccia|first3 = D|last4 = Herger|first4 = R|last5 = Willmott|first5 = P|last6 = Patterson|first6 = B|last7 = Osterwalder|first7 = J|last8 = Vanderveen|first8 = J|last9 = Greber|first9 = T|issue = 2}}</ref> and some liquids,<ref name="berner07">{{cite journal|author = S. Berner|title = Boron Nitride Nanomesh: Functionality from a Corrugated Monolayer|journal=Angew. Chem. Int. Ed.|volume = 46|issue = 27 |pages = 5115–5119 |doi = 10.1002/anie.200700234|pmid = 17538919|year = 2007|last2 = Corso|first2 = Martina|last3 = Widmer|first3 = Roland|last4 = Groening|first4 = Oliver|last5 = Laskowski|first5 = Robert|last6 = Blaha|first6 = Peter|last7 = Schwarz|first7 = Karlheinz|last8 = Goriachko|first8 = Andrii|last9 = Over|first9 = Herbert}}</ref><ref name="widmer07">{{cite journal|author = R. Widmer|title = Electrolytic in situ STM investigation of h-BN-Nanomesh|journal=Electrochem. Comm.|volume = 9 |pages = 2484–2488 |doi = 10.1016/j.elecom.2007.07.019| year = 2007|last2 = Berner|first2 = S|last3 = Groning|first3 = O|last4 = Brugger|first4 = T|last5 = Osterwalder|first5 = J|last6 = Greber|first6 = T|issue = 10}}</ref> but also up to temperatures of 800&nbsp;°C.<ref name="corso04"/> In addition, it shows the extraordinary ability to trap ]<ref name="berner07"/> and metallic ]<ref name="goriachko07"/> which have similar sizes to the nanomesh pores, forming a well-ordered array. These characteristics promise interesting applications of the nanomesh in areas like nanocatalysis, ], ], ] and data storage media like ]s.<ref>{{cite web|url=http://www.nanomesh.ch/history.php| title= The discovery of the nanomesh for everyone| accessdate=2009-06-06}}</ref>
	===Boron nitride nanotubes===		===Boron nitride nanotubes===
			{{Main|Boron nitride nanotube}} Boron nitride tubules were first made in 1989 by Shore and Dolan This work was patented in 1989 and published in 1989 thesis (Dolan) and then 1993 Science. The 1989 work was also the first preparation of amorphous BN by B-trichloroborazine and cesium metal.
	{{see also|Carbon nanotube}}
	Boron nitride nanotubes were theoretically predicted in 1994<ref>{{cite journal|doi=10.1103/PhysRevB.49.5081|title=Theory of graphitic boron nitride nanotubes|year=1994|last1=Rubio|first1=Angel|last2=Corkill|first2=Jennifer|last3=Cohen|first3=Marvin|journal=Physical Review B|volume=49|pages=5081|issue=7}}</ref> and experimentally discovered in 1995.<ref name="N.G. Chopra, R.J. Luyken 1995">{{cite journal|doi=10.1126/science.269.5226.966|title=Boron Nitride Nanotubes|year=1995|last1=Chopra|first1=N. G.|last2=Luyken|first2=R. J.|last3=Cherrey|first3=K.|last4=Crespi|first4=V. H.|last5=Cohen|first5=M. L.|last6=Louie|first6=S. G.|last7=Zettl|first7=A.|journal=Science|volume=269|pages=966|pmid=17807732|issue=5226}}</ref> They can be imagined as a rolled up sheet of boron nitride. Structurally, it is a close analog of the carbon nanotube, namely a long cylinder with diameter of several to hundred nanometers and length of many micrometers, except carbon atoms are alternately substituted by nitrogen and boron atoms. However, the properties of BN nanotubes are very different: whereas carbon nanotubes can be metallic or semiconducting depending on the rolling direction and radius, a BN nanotube is an electrical insulator with a bandgap of ~5.5 eV, basically independent of tube chirality and morphology.<ref>{{cite journal|doi=10.1209/0295-5075/28/5/007|title=Stability and Band Gap Constancy of Boron Nitride Nanotubes|year=1994|last1=Blase|first1=X|last2=Rubio|first2=A|last3=Louie|first3=S. G|last4=Cohen|first4=M. L|journal=Europhysics Letters (EPL)|volume=28|pages=335|issue=5}}</ref> In addition, a layered BN structure is much more thermally and chemically stable than a graphitic carbon structure.<ref>{{cite journal|url=http://www.glue.umd.edu/~cumings/PDF%20Publications/15.APL81han.pdf|doi=10.1063/1.1498494|title=Transformation of BCN nanotubes to pure BN nanotubes|year=2002|last1=Han|first1=Wei-Qiang|last2=Mickelson|first2=W.|last3=Cumings|first3=John|last4=Zettl|first4=A.|journal=Applied Physics Letters|volume=81|pages=1110|issue=6}}</ref><ref name=golberg>{{cite journal| author = D. Golberg, Y. Bando, C.C. Tang, C.Y. Zhi |title = Boron nitride nanotubes|doi = 10.1002/adma.200700179 |journal = Adv. Mater. |volume = 19|year =2007 |page = 2413| issue = 18}}</ref>
	All well-established techniques of carbon nanotube growth, such as arc-discharge,<ref name="N.G. Chopra, R.J. Luyken 1995"/><ref>{{cite journal|doi=10.1016/S0009-2614(99)01277-4|title=Mass-production of boron nitride double-wall nanotubes and nanococoons|year=2000|last1=Cumings|first1=J|journal=Chemical Physics Letters|volume=316|pages=211|bibcode=2000CPL...316..211C|issue=3–4}}</ref> laser ablation<ref>{{cite journal|doi=10.1063/1.116874|title=Nanotubes in boron nitride laser heated at high pressure|year=1996|last1=Golberg|first1=D.|last2=Bando|first2=Y.|last3=Eremets|first3=M.|last4=Takemura|first4=K.|last5=Kurashima|first5=K.|last6=Yusa|first6=H.|journal=Applied Physics Letters|volume=69|pages=2045|issue=14}}</ref><ref>{{cite journal|doi=10.1063/1.121236|title=Synthesis of boron nitride nanotubes by means of excimer laser ablation at high temperature|year=1998|last1=Yu|first1=D. P.|last2=Sun|first2=X. S.|last3=Lee|first3=C. S.|last4=Bello|first4=I.|last5=Lee|first5=S. T.|last6=Gu|first6=H. D.|last7=Leung|first7=K. M.|last8=Zhou|first8=G. W.|last9=Dong|first9=Z. F.|journal=Applied Physics Letters|volume=72|pages=1966|issue=16}}</ref> and chemical vapor deposition,<ref>{{cite journal|doi=10.1016/j.ssc.2005.03.062|title=Effective precursor for high yield synthesis of pure BN nanotubes|year=2005|last1=Zhi|first1=C|last2=Bando|first2=Y|last3=Tan|first3=C|last4=Golberg|first4=D|journal=Solid State Communications|volume=135|pages=67}}</ref> are used to synthesize BN nanotubes. BN nanotubes can also be produced by ]ing of amorphous boron, mixed with a catalyst: iron powder, under NH<sub>3</sub> atmosphere. Subsequent annealing at ~1100&nbsp;°C in nitrogen flow transforms most of the product into BN.<ref name=Au/><ref name=eu/>
			Boron nitride nanotubes were predicted in 1994<ref>{{cite journal | doi = 10.1103/PhysRevB.49.5081 | pmid = 10011453 | title = Theory of Graphitic Boron Nitride Nanotubes | year = 1994 | author = Rubio, A. | journal = Physical Review B | volume = 49 | issue = 7 | pages = 5081–5084 |bibcode = 1994PhRvB..49.5081R | url = https://zenodo.org/record/1233727 |display-authors=etal}}</ref> and experimentally discovered in 1995.<ref name="N.G. Chopra, R.J. Luyken 1995">{{cite journal | doi = 10.1126/science.269.5226.966 | title = Boron Nitride Nanotubes | year = 1995 | author = Chopra, N. G. | journal = Science | volume = 269 | pages = 966–7 | pmid = 17807732 | issue = 5226 |bibcode = 1995Sci...269..966C | s2cid = 28988094 |display-authors=etal}}</ref> They can be imagined as a rolled up sheet of h-boron nitride. Structurally, it is a close analog of the ], namely a long cylinder with diameter of several to hundred nanometers and length of many micrometers, except carbon atoms are alternately substituted by nitrogen and boron atoms. However, the properties of BN nanotubes are very different: whereas carbon nanotubes can be metallic or semiconducting depending on the rolling direction and radius, a BN nanotube is an electrical insulator with a bandgap of ~5.5 eV, basically independent of tube chirality and morphology.<ref>{{cite journal | doi = 10.1209/0295-5075/28/5/007 | title = Stability and Band Gap Constancy of Boron Nitride Nanotubes | year = 1994 | author = Blase, X. | s2cid = 120010610 | journal = Europhysics Letters (EPL) | volume = 28 | page = 335 | issue = 5 |bibcode = 1994EL.....28..335B |display-authors=etal}}</ref> In addition, a layered BN structure is much more thermally and chemically stable than a graphitic carbon structure.<ref>{{cite journal | url = http://www.glue.umd.edu/~cumings/PDF%20Publications/15.APL81han.pdf | doi = 10.1063/1.1498494 | title = Transformation of B<sub>x</sub>C<sub>y</sub>N<sub>z</sub> Nanotubes to Pure BN Nanotubes | year = 2002 | author = Han, Wei-Qiang | journal = Applied Physics Letters | volume = 81 | page = 1110 | issue = 6 |bibcode = 2002ApPhL..81.1110H |display-authors=etal}}</ref><ref name="golberg">{{cite journal | title = Boron Nitride Nanotubes | doi = 10.1002/adma.200700179 | journal = Advanced Materials | volume = 19 | year = 2007 | page = 2413 | issue = 18 | last1 = Golberg | first1 = D. | last2 = Bando | first2 = Y. | last3 = Tang | first3 = C. C. | last4 = Zhi | first4 = C. Y. | bibcode = 2007AdM....19.2413G | s2cid = 221149452}}</ref>
	Electrical and field emission properties of the thus prepared nanotubes can be tuned by doping with gold atoms via sputtering of gold on the nanotubes.<ref name=Au>{{cite journal| author= H. Chen| title=Nano Au-decorated boron nitride nanotubes: Conductance modification and field-emission enhancement|journal =Appl. Phys. Lett. |volume =92 |page =243105 |year =2008| doi = 10.1063/1.2943653| url =http://wwwrsphysse.anu.edu.au/nanotube/pdf/aubnntapl08.pdf| last2= Zhang| first2= Hongzhou| last3= Fu| first3= Lan| last4= Chen| first4= Ying| last5= Williams| first5= James S.| last6= Yu| first6= Chao| last7= Yu| first7= Dapeng| issue= 24}}</ref><ref>{{cite journal|author= Y. Chen |title =Au doped BN nanotubes with tunable conductivity| journal = Nano| volume = 2| year =2008| page = 367| doi =10.1142/S1793292007000702|last2= Fu|first2= L.|last3= Chen|first3= Y.|last4= Zou|first4= J.|last5= Li|first5= J.|last6= Duan|first6= W. H.|issue= 06}}</ref> Doping rare-earth atoms of ] turns a BN nanotube into a ] material emitting visible light under electron excitation.<ref name=eu>{{cite journal| author = H. Chen |title =Eu-doped Boron Nitride Nanotubes as a Nanometer-Sized Visible-Light Source| journal = Advanced Materials |year =2007 |volume = 19 |page = 1845| doi = 10.1002/adma.200700493|url =http://wwwrsphysse.anu.edu.au/nanotube/pdf/Eu-BNNTs.pdf| last2 = Chen| first2 = Y.| last3 = Li| first3 = C. P.| last4 = Zhang| first4 = H.| last5 = Williams| first5 = J. S.| last6 = Liu| first6 = Y.| last7 = Liu| first7 = Z.| last8 = Ringer| first8 = S. P.| issue = 14}}</ref>
			===Boron nitride aerogel===
	Like BN fibers, boron nitride nanotubes show promise for aerospace applications where integration of boron and in particular the light isotope of boron (<sup>10</sup>B) into structural materials improves their radiation-shielding properties; the improvement is due to strong neutron absorption by <sup>10</sup>B. Such <sup>10</sup>BN materials are of particular theoretical value as composite structural materials in future manned interplanetary spacecraft, where absorption-shielding from cosmic ray ] neutrons is expected to be a particular asset in light construction materials.<ref>{{cite journal|author= J. Yu| title = Isotopically Enriched 10BN Nanotubes| journal=Advanced Materials| volume =18|year =2006| url =http://www.rsphysse.anu.edu.au/nanotube/pdf/B10Nnanotubes.pdf |doi =10.1002/adma.200600231|pages= 2157|last2= Chen|first2= Y.|last3= Elliman|first3= R. G.|last4= Petravic|first4= M.|issue= 16}}</ref>
			{{Main|Boron nitride aerogel}}
			Boron nitride aerogel is an ] made of highly porous BN. It typically consists of a mixture of deformed BN nanotubes and ]. It can have a density as low as 0.6&nbsp;mg/cm<sup>3</sup> and a specific surface area as high as 1050&nbsp;m<sup>2</sup>/g, and therefore has potential applications as an ], catalyst support and gas storage medium. BN aerogels are highly ] and can absorb up to 160 times their weight in oil. They are resistant to oxidation in air at temperatures up to 1200&nbsp;°C, and hence can be reused after the absorbed oil is burned out by flame. BN aerogels can be prepared by template-assisted ] using ] as the feed gas.<ref name=nat/>
	===Composites containing BN===		===Composites containing BN===
	Addition of boron nitride to ] ceramics improves the ] resistance of the resulting material. For the same purpose, BN is added also to silicon nitride-] and ]-alumina ceramics. Other materials being reinforced with BN are, e.g., alumina and ], ]es, ]s, ], and composite ceramics with ]-boron nitride and titanium boride-]-boron nitride and ]-boron nitride composition.<ref>{{cite book| title = Handbook of Composite Reinforcements|author = S. M. Lee| publisher = John Wiley and Sons |year = 1992 |isbn = 0471188611}}</ref>		Addition of boron nitride to ] ceramics improves the ] resistance of the resulting material. For the same purpose, BN is added also to silicon nitride-] and ]-alumina ceramics. Other materials being reinforced with BN include alumina and ], ]es, ]s, ], and composite ceramics with ]-boron nitride, titanium boride-]-boron nitride, and ]-boron nitride composition.<ref>{{cite book | title = Handbook of Composite Reinforcements | author = Lee, S. M. | publisher = John Wiley and Sons | year = 1992 | isbn = 978-0471188612}}</ref>
			Zirconia Stabilized Boron Nitride (ZSBN) is produced by adding ] to BN, enhancing its thermal shock resistance and mechanical strength through a ] process.<ref>{{cite web |url=https://www.preciseceramic.com/blog/boron-nitride-variants-pbn-hbn-cbn-zsbn.html |title=Diverse Classification Factors of Boron Nitride and Their Correlation with PBN, HBN, CBN, and ZSBN Variants
			|last=Lisa |first=Ross |website=Precise Ceramics |access-date=June 8, 2024}}</ref> It offers better performance characteristics including Superior ] and ] resistance over a wide temperature range.<ref>{{cite book |author=<!-- Not Stated --> |title=New Steel: Mini & Integrated Mill Management and Technologies |date=1996 |publisher=Chilton Publishing |pages=51–56}}</ref> Its unique combination of thermal conductivity, ], mechanical strength, and stability makes it suitable for various applications including cutting tools and wear-resistant coatings, thermal and electrical insulation, aerospace and defense, and high-temperature components.<ref>{{cite journal |last1=Hayat |first1=Asif |last2=Sohail |first2=Muhammad |last3=Hamdy |first3=Mohamed |date=2022 |title=Fabrication, characteristics, and applications of boron nitride and their composite nanomaterials |url=https://www.sciencedirect.com/science/article/abs/pii/S2468023022000062 |journal=Surfaces and Interfaces |volume=29 |doi=10.1016/j.surfin.2022.101725 |access-date=June 8, 2024}}</ref><ref>{{cite journal |last1=Eichler |first1=Jens |last2=Lesniak |first2=Cristoph |date=2008 |title=Boron nitride (BN) and BN composites for high-temperature applications |url=https://www.sciencedirect.com/science/article/abs/pii/S0955221907004700 |journal=Journal of the European Ceramic Society |volume=28 |issue=5 |pages=1105–1109 |doi=10.1016/j.jeurceramsoc.2007.09.005}}</ref>
			===Pyrolytic boron nitride (PBN)===
			Pyrolytic boron nitride (PBN), also known as ] Boron Nitride(CVD-BN),<ref>{{cite web |url=https://www.preciseceramic.com/blog/introduction-of-pyrolytic-boron-nitride-pbn.html |title=About Pyrolytic Boron Nitride |last=Rose |first=Lisa |website=Precise Ceramic |access-date=May 31, 2024}}</ref> is a high-purity ] material characterized by exceptional chemical resistance and mechanical strength at high temperatures.<ref>{{cite web |title=Pyrolytic Boron Nitride (PBN) |url=https://www.shinetsu.co.jp/en/products/electronics-materials/pyrolytic-boron-nitride-pbn/ |website=Shin-Etsu Chemical Co., Ltd. |access-date=May 31, 2024}}</ref>
			Pyrolytic boron nitride is typically prepared through the thermal decomposition of ] and ] vapors on ] substrates at 1900°C.<ref>{{cite journal |last1=Moore |first1=A. |title=Compression Annealing of Pyrolytic Boron Nitride |journal=Nature |volume=221 |pages=1133–1135 |date=1969-03-22 |issue=5186 |doi=10.1038/2211133a0 |bibcode=1969Natur.221.1133M |url=https://www.nature.com/articles/2211133a0 |access-date=May 31, 2024}}</ref>
			Pyrolytic boron nitride (PBN) generally has a hexagonal structure similar to hexagonal boron nitride (hBN), though it can exhibit stacking faults or deviations from the ideal lattice.<ref>{{cite web |title=An Overview of Pyrolytic Boron Nitride (PBN) |url=https://www.sputtertargets.net/an-overview-of-pyrolytic-boron-nitride-pbn.html |website=Sputter Targets |date=3 December 2018 |access-date=May 31, 2024}}</ref> Pyrolytic boron nitride (PBN) shows some remarkable attributes, including exceptional chemical inertness, high ] strength, excellent thermal shock resistance, non-wettability, non-toxicity, oxidation resistance, and minimal ].
			<ref>{{cite journal |last1=Lipp |first1=A. |last2=Schwetz |first2=K.A. |last3=Hunold |first3=K. |title=Hexagonal boron nitride: Fabrication, properties and applications |journal=Journal of the European Ceramic Society |volume=5 |issue=1 |pages=3–9 |date=1989 |doi=10.1016/0955-2219(89)90003-4 }}</ref><ref>{{cite journal |last1=Moore |first1=A.W. |title=Characterization of pyrolytic boron nitride for semiconductor materials processing |journal=Journal of Crystal Growth |volume=106 |issue=1 |pages=6–15 |date=1990 |doi=10.1016/0022-0248(90)90281-O |bibcode=1990JCrGr.106....6M }}</ref>
			Due to a highly ordered planar texture similar to pyrolytic graphite (PG), it exhibits anisotropic properties such as lower ] constant vertical to the ] plane and higher bending strength along the ] plane.<ref>{{cite journal |last1=Rebillat |first1=F. |last2=Guette |first2=A. |title=Highly ordered pyrolytic BN obtained by LPCVD |journal=Journal of the European Ceramic Society |volume=17 |issue=12 |pages=1403–1414 |date=1997 |doi=10.1016/S0955-2219(96)00244-0}}</ref> PBN material has been widely manufactured as ] of compound ] crystals, output windows and ] rods of traveling-wave tubes, high-temperature ] and ].<ref>{{cite journal |last1=Gao |first1=Shitao |last2=Li |first2=Bin |title=Micromorphology and structure of pyrolytic boron nitride synthesized by chemical vapor deposition from borazine |journal=Ceramics International |volume=44 |issue=10 |pages=11424–11430 |date=2018 |doi=10.1016/j.ceramint.2018.03.201}}</ref>
	==Health issues==		==Health issues==
			Boron nitride (along with {{chem2|Si3N4}}, NbN, and BNC) is generally considered to be non-toxic and does not exhibit chemical activity in biological systems.<ref>{{Cite web |title=EWG Skin Deep® {{!}} What is BORON NITRIDE |url=http://www.ewg.org/skindeep/ingredients/700802-BORON_NITRIDE/ |access-date=2023-07-26 |website=EWG |language=en}}</ref> Due to its excellent safety profile and lubricious properties, boron nitride finds widespread use in various applications, including cosmetics and food processing equipment.<ref>{{Cite web |title=UNII - 2U4T60A6YD |url=https://precision.fda.gov/uniisearch/srs/unii/2u4t60a6yd |access-date=2023-07-26 |website=precision.fda.gov}}</ref><ref>{{Cite web|url=https://info.nsf.org/USDA/letters/153558.pdf|title=NSF International / Nonfood Compounds Registration Program}}</ref>
	Boron nitride (along with Si<sub>3</sub>N<sub>4</sub>, NbN, and BNC) is reported to show weak ] activity and cause ]. The maximum concentration recommended for nitrides of nonmetals is 10&nbsp;mg/m<sup>3</sup> for BN and 4 for AlN or ZrN.<ref name=BN/>
	==See also==		==See also==
			* ]
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			==Notes==
			{{noteslist}}
			==References==
	==Notes and references==
	{{Reflist|2}}		{{Reflist|30em}}
	==External links==		==External links==
			{{Commons category|Boron nitride}}
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	* at University of Oxford		* at University of Oxford
	{{Boron compounds}}		{{Boron compounds}}
			{{Nitrides}}
	{{good article}}		{{good article}}
			{{Authority control}}
	{{DEFAULTSORT:Boron Nitride}}		{{DEFAULTSORT:Boron Nitride}}
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