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Revision as of 13:16, 15 February 2012 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Saving copy of the {{chembox}} taken from revid 472543797 of page Calcium_fluoride for the Chem/Drugbox validation project (updated: '').		Latest revision as of 01:08, 8 November 2024 edit Mikhail Ryazanov (talk | contribs)Extended confirmed users23,609 editsm →top: fmt., punct.
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			{{Chembox
	{{ambox | text = This page contains a copy of the infobox ({{tl|chembox}}) taken from revid of page ] with values updated to verified values.}}
	{{chembox
	| Watchedfields = changed		| Watchedfields = changed
	| verifiedrevid = 443495777		| verifiedrevid = 476999594
	| ImageFileL1 = Calcium fluoride.jpg		| ImageFileL1 = Calcium fluoride.jpg
	| ImageSizeL1 = 150 px
	| ImageFileR1 = Fluorite-unit-cell-3D-ionic.png		| ImageFileR1 = Fluorite-unit-cell-3D-ionic.png
	| ImageSizeR1 = 150 px
	| ImageFile2 = Fluorid vápenatý.PNG		| ImageFile2 = Fluorid vápenatý.PNG
	| ImageSize2 =		| ImageSize2 =
	| IUPACName =		| IUPACName =
	| OtherNames =		| OtherNames =
	| Section1 = {{Chembox Identifiers		|Section1={{Chembox Identifiers
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}		| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| ChemSpiderID = 23019		| ChemSpiderID = 23019
	| UNII_Ref = {{fdacite|correct|FDA}}		| UNII_Ref = {{fdacite|correct|FDA}}
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	| ChEBI = 35437		| ChEBI = 35437
	| SMILES = ..		| SMILES = ..
			| SMILES1 = FF
	| InChIKey = WUKWITHWXAAZEY-NUQVWONBAZ		| InChIKey = WUKWITHWXAAZEY-NUQVWONBAZ
	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}		| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
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	| StdInChIKey = WUKWITHWXAAZEY-UHFFFAOYSA-L		| StdInChIKey = WUKWITHWXAAZEY-UHFFFAOYSA-L
	| CASNo = 7789-75-5		| CASNo = 7789-75-5
	| CASNo_Ref = {{cascite|correct|CAS}}		| CASNo_Ref = {{cascite|correct|CAS}}
	| EINECS = 232-188-7		| EINECS = 232-188-7
	| PubChem = 24617		| PubChem = 24617
	| RTECS = EW1760000		| RTECS = EW1760000
	}}
	| Section2 = {{Chembox Properties
	| Formula = |Ca=1|F=2
	| ExactMass = 77.959398
	| Appearance = White crystalline solid (single crystals are transparent)
	| Density = 3.18 g/cm<sup>3</sup>
	| MeltingPtC = 1418
	| BoilingPtC = 2533
	| Solubility = 0.0015 g/100 mL (18 °C) <br> 0.0016 g/100 mL (20 °C)
	| SolubilityProduct = 3.9 x 10<sup>-11</sup> <ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, ISBN 0070494398</ref>
	| SolubleOther = insoluble in ] <br> slightly soluble in acid
	| RefractIndex = 1.4338
	}}		}}
	| Section3 = {{Chembox Structure		|Section2={{Chembox Properties
			| Formula = | Ca=1 | F=2
	| CrystalStruct = ], ]<ref>X-ray Diffraction Investigations of CaF<sub>2</sub> at High Pressure, L. Gerward, J. S. Olsen, S. Steenstrup, M. Malinowski, S. Åsbrink and A. Waskowska, Journal of Applied Crystallography (1992), 25, 578-581 {{ doi|10.1107/S0021889892004096}}</ref>
			| Appearance = White crystalline solid (single crystals are transparent)
	| SpaceGroup = Fm<u style="text-decoration:overline">3</u>m, #225
			| Density = 3.18 g/cm<sup>3</sup>
	| Coordination = Ca, 8, cubic<br />F, 4, tetrahedral
	| LattConst_a =		| MeltingPtC = 1418
	| LattConst_b =		| BoilingPtC = 2533
			| Solubility = 0.015 g/L (18 °C)<br>0.016 g/L (20 °C)
	| LattConst_c =
			| SolubilityProduct = 3.9 × 10<sup>−11</sup> <ref>Pradyot Patnaik. ''Handbook of Inorganic Chemicals''. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}.</ref>
	| LattConst_alpha =
			| SolubleOther = insoluble in ]<br>slightly soluble in acid
	| LattConst_beta =
			| RefractIndex = 1.4338
	| LattConst_gamma =
			| MagSus = −28.0·10<sup>−6</sup> cm<sup>3</sup>/mol
	| MolShape =
	| OrbitalHybridisation =
	| Dipole =
	}}		}}
	| Section4 = {{Chembox Hazards		|Section3={{Chembox Structure
			| CrystalStruct = ], ]<ref>X-ray Diffraction Investigations of CaF<sub>2</sub> at High Pressure, L. Gerward, J. S. Olsen, S. Steenstrup, M. Malinowski, S. Åsbrink and A. Waskowska, Journal of Applied Crystallography (1992), 25, 578–581, {{doi|10.1107/S0021889892004096}}.</ref>
	| MainHazards = Reacts with conc. ] to produce ]
			| SpaceGroup = Fm{{overline|3}}m, #225
	| EUIndex = Not listed
			| Coordination = Ca, 8, cubic<br/>F, 4, tetrahedral
	| External MSDS =
			| LattConst_a = 5.451 Å
	| RPhrases = {{R20}}, {{R22}}, {{R36}}, {{R37}}, {{R38}}
			| LattConst_b = 5.451 Å
	| SPhrases = {{S26}}, {{S36}}
			| LattConst_c = 5.451 Å
	| NFPA-H = 0
	| NFPA-F = 0		| LattConst_alpha = 90
			| LattConst_beta =
	| NFPA-R = 0
			| LattConst_gamma =
	| NFPA-O =
			| MolShape =
	| FlashPt = Non-flammable
			| OrbitalHybridisation =
	| LD50 = 4250 mg/kg (oral, rat)
			| Dipole =
	}}
	| Section8 = {{Chembox Related
	| OtherAnions = ]<br/>]<br/>]
	| OtherCations = ]<br/>]<br/>]<br/>]
	}}
	}}		}}
			|Section4={{Chembox Hazards
			| MainHazards = Reacts with concentrated ] to produce ]
			| ExternalSDS =
			| NFPA-H = 0
			| NFPA-F = 0
			| NFPA-R = 0
			| NFPA-S =
			| FlashPt = Non-flammable
			| LDLo = >5000 mg/kg (oral, guinea pig)<br/>4250 mg/kg (oral, rat)<ref>{{IDLH|fluoride|Fluorides (as F)}}</ref>
			}}
			|Section8={{Chembox Related
			| OtherAnions = ]<br/>]<br/>]
			| OtherCations = ]<br/>]<br/>]<br/>]
			}}
			}}
			'''Calcium fluoride''' is the ] of the elements ] and ] with the ] CaF<sub>2</sub>. It is a white solid that is practically insoluble in water. It occurs as the mineral ] (also called fluorspar), which is often deeply coloured owing to impurities.
			==Chemical structure==
			{{main|Fluorite structure}}
			The compound crystallizes in a cubic motif called the ].
			]
			Ca<sup>2+</sup> centres are eight-coordinate, being centred in a cube of eight F<sup>−</sup> centres. Each F<sup>−</sup> centre is coordinated to four Ca<sup>2+</sup> centres in the shape of a tetrahedron.<ref>G. L. Miessler and D. A. Tarr "Inorganic Chemistry" 3rd Ed, Pearson/Prentice Hall publisher, {{ISBN|0-13-035471-6}}.</ref> Although perfectly packed crystalline samples are colorless, the mineral is often deeply colored due to the presence of ]s.
			The same crystal structure is found in numerous ionic compounds with formula AB<sub>2</sub>, such as ], ], ], ], and ]. In the corresponding ], called the antifluorite structure, anions and cations are swapped, such as ].
			===Gas phase===
			The gas phase is noteworthy for failing the predictions of ]; the {{chem2|CaF2}} molecule is not linear like {{chem2|MgF2}}, but bent with a ] of approximately 145°; the strontium and barium dihalides also have a bent geometry.<ref>{{Greenwood&Earnshaw}}</ref> It has been proposed that this is due to the fluoride ]s interacting with the electron core<ref name = "Gillespie&Robinson">{{cite journal | last1 = Gillespie | first1 = R. J. | last2 = Robinson | first2 = E. A. | year = 2005 | title = Models of molecular geometry | journal = ] | volume = 34 | issue = 5| pages = 396–407 | doi = 10.1039/b405359c | pmid = 15852152 }}</ref><ref name = "Bytheway&Gillespie">{{cite journal | last1 = Bytheway | first1 = I. | last2 = Gillespie | first2 = R. J. | last3 = Tang | first3 = T. H. | last4 = Bader | first4 = R.F | year = 1995 | title = Core Distortions and Geometries of the Difluorides and Dihydrides of Ca, Sr, and Ba | journal = ] | volume = 34 | issue = 9| pages = 2407–2414 | doi = 10.1021/ic00113a023 }}</ref> or the d-subshell<ref>{{cite journal | doi = 10.1063/1.459748 | title = Ab initio model potential study of the equilibrium geometry of alkaline earth dihalides: MX<sub>2</sub> (M=Mg, Ca, Sr, Ba; X=F, Cl, Br, I) | year = 1991 | author = Seijo, Luis | journal = ] | volume = 94 | pages = 3762 | last2 = Barandiarán | first2 = Zoila | last3 = Huzinaga | first3 = Sigeru | issue = 5| bibcode = 1991JChPh..94.3762S | url = https://repositorio.uam.es/bitstream/10486/7315/1/41581_jchemphysseijo_91_jcp_94_3762.pdf | hdl = 10486/7315 | hdl-access = free }}</ref> of the calcium atom.
			==Preparation==
			The mineral ] is abundant, widespread, and mainly of interest as a precursor to ]. Thus, little motivation exists for the industrial production of CaF<sub>2</sub>. High purity CaF<sub>2</sub> is produced by treating ] with ]:<ref name=Aigueperse>{{Ullmann|doi=10.1002/14356007.a11_307|title=Fluorine Compounds, Inorganic|year=2000|last1=Aigueperse|first1=Jean|last2=Mollard|first2=Paul|last3=Devilliers|first3=Didier|last4=Chemla|first4=Marius|last5=Faron|first5=Robert|last6=Romano|first6=René|last7=Cuer|first7=Jean Pierre|isbn=3527306730}}</ref>
			:CaCO<sub>3</sub> + 2 HF → CaF<sub>2</sub> + CO<sub>2</sub> + H<sub>2</sub>O
			==Applications==
			{{Main|Fluorite}}
			Naturally occurring CaF<sub>2</sub> is the principal source of ], a commodity chemical used to produce a wide range of materials.
			Calcium fluoride in the ] state is of significant commercial importance as a fluoride source.<ref>Aigueperse, Jean; Mollard, Paul; Devilliers, Didier; Chemla, Marius; Faron, Robert; Romano, Renée; Cuer, Jean Pierre (2005), "Fluorine Compounds, Inorganic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, p. 307, doi:10.1002/14356007.a11_307.</ref> Hydrogen fluoride is liberated from the mineral by the action of concentrated ]:<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}.</ref>
			:CaF<sub>2</sub> + H<sub>2</sub>SO<sub>4</sub> → ](solid) + 2 HF
			===Others===
			Calcium fluoride is used to manufacture optical components such as windows and lenses, used in thermal imaging systems, spectroscopy, ]s, and ]s (used for ] in the form of a fused lens). It is transparent over a broad range from ultraviolet (UV) to infrared (IR) frequencies. Its low refractive index reduces the need for ]s. Its insolubility in water is convenient as well.{{Cn|date=June 2022}} It also allows much smaller wavelengths to pass through.{{Cn|date=June 2022}}
			Doped calcium fluoride, like natural fluorite, exhibits ] and is used in ]s. It forms when fluorine combines with calcium.{{Cn|date=June 2022}}
			==Safety==
			CaF<sub>2</sub> is classified as "not dangerous", although reacting it with ] produces ], which is highly corrosive and toxic. With regards to inhalation, the ]-recommended concentration of fluorine-containing dusts is 2.5&nbsp;mg/m<sup>3</sup> in air.<ref name=Aigueperse/>
			==See also==
			*]
			*]
			*]
			==References==
			{{Reflist}}
			==External links==
			* thermochemistry data
			*
			*
			* {{Webarchive|url=https://web.archive.org/web/20121110090919/http://www.crystran.co.uk/calcium-fluoride-caf2.htm |date=2012-11-10 }}
			* {{Webarchive|url=https://web.archive.org/web/20111121195835/http://msds.chem.ox.ac.uk/CA/calcium_fluoride.html |date=2011-11-21 }} (University of Oxford)
			{{Calcium compounds}}
			{{Fluorides}}
			]
			]
			]
			]
			]
			]
			]