Browse history interactively

Page 1

Page 1Revision 1

Page 2

Page 2Revision 2

← Previous editContent deleted Content addedVisualWikitext

Revision as of 06:40, 8 November 2011 editBeetstra (talk | contribs)Edit filter managers, Administrators172,031 edits Script assisted update of identifiers for the Chem/Drugbox validation project (updated: 'ChEMBL').← Previous edit		Latest revision as of 11:55, 15 October 2024 edit undoRoi.Frvr (talk | contribs)283 editsm added linkTag: Visual edit
(435 intermediate revisions by more than 100 users not shown)
Line 1:		Line 1:
			{{Short description|Inorganic salt: MgCl2 and its hydrates}}
	{{chembox		{{chembox
	| Verifiedfields = changed		| Watchedfields = changed
	| verifiedrevid = 400501725		| verifiedrevid = 459589655
	| ImageFile = Magnesium chloride.jpg		| ImageFile1 = Magnesium chloride.jpg
			| ImageFile2 = Cadmium-chloride-3D-balls.png
	| ImageSize = 200px
	| ImageFile1 = Magnesium-chloride-3D-polyhedra.png		| OtherNames = {{Unbulleted list|Magnesium dichloride}}
			|Section1={{Chembox Identifiers
	| IUPACName = Magnesium chloride
	| SystematicName =
	| OtherNames = Magnesium dichloride
	| Section1 = {{Chembox Identifiers
	| Abbreviations =		| Abbreviations =
	| CASNo = 7786-30-3		| CASNo = 7786-30-3
	| CASNo_Ref = {{cascite|correct|CAS}}		| CASNo_Ref = {{cascite|correct|CAS}}
			| CASNo2_Ref = {{cascite|correct|CAS}}
	| CASOther = <br/>7791-18-6 (hexahydrate) <!--also verified against the Chemical Abstracts Service list -->
	| EINECS =		| CASNo2 = 7791-18-6
			| CASNo2_Comment = (hexahydrate) <!--also verified against the Chemical Abstracts Service list -->
	| EINECSCASNO =
	| PubChem = 24584
	| ChEMBL_Ref = {{ebicite|changed|EBI}}		| ChEMBL_Ref = {{ebicite|changed|EBI}}
	| ChEMBL = <!-- blanked - oldvalue: 1200547 -->		| ChEMBL = 1200547
	| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}		| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
	| ChemSpiderID = 22987		| ChemSpiderID = 22987
	| ChEBI_Ref = {{ebicite|changed|EBI}}		| ChEBI_Ref = {{ebicite|correct|EBI}}
	| ChEBI = 6636		| ChEBI = 6636
	| SMILES = ..		| EINECS = 232-094-6
			| Gmelin = 9305
	| InChI = InChI=1S/2ClH.Mg/h2*1H;/q;;+2/p-2
			| PubChem = 24584
	| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
			| RTECS = OM2975000
			| UNII_Ref = {{fdacite|correct|FDA}}
			| UNII = 59XN63C8VM
			| UNII2_Ref = {{fdacite|correct|FDA}}
			| UNII2 = 02F3473H9O
			| UNII2_Comment = (hexahydrate)
			| InChI = InChI=1S/2ClH.Mg/h2*1H;/q;;+2/p-2
			| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
	| StdInChI = 1S/2ClH.Mg/h2*1H;/q;;+2/p-2		| StdInChI = 1S/2ClH.Mg/h2*1H;/q;;+2/p-2
	| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}		| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
	| StdInChIKey = TWRXJAOTZQYOKJ-UHFFFAOYSA-L		| StdInChIKey = TWRXJAOTZQYOKJ-UHFFFAOYSA-L
	| RTECS = OM2975000		| SMILES = ClCl
			| SMILES2 = ..
	}}		}}
	| Section2 = {{Chembox Properties		|Section2={{Chembox Properties
	| Formula = MgCl<sub>2</sub>		| Formula = {{chem2|MgCl2}}
	| MolarMass = 95.211 g/mol (anhydrous)<br/>203.31 g/mol (hexahydrate)		| MolarMass = 95.211 g/mol (anhydrous)<br />203.31 g/mol (hexahydrate)
	| Appearance = white or colourless crystalline solid		| Appearance = white or colourless crystalline solid
	| Density = 2.32 g/cm<sup>3</sup> (anhydrous) <br> 1.569 g/cm<sup>3</sup> (hexahydrate)		| Density = 2.32 g/cm<sup>3</sup> (anhydrous)<br />1.569 g/cm<sup>3</sup> (hexahydrate)
	| MeltingPt = 714 °C (987 K)		| MeltingPtC = 714
	| Melting_notes = on rapid heating: slow heating leads to decomposition from 300&nbsp;°C		| MeltingPt_notes = <br>anhydrous<br>{{convert|117|C|F K}}<br>hexahydrate on rapid heating; slow heating leads to decomposition from {{convert|300|C|F K}}
	| BoilingPt = 1412 °C (1685 K)		| BoilingPtC = 1412
	| Boiling_notes =		| BoilingPt_notes =
	| Solubility = ''anhydrous'' <br> 54.3 g/100 ml (20 °C) <br> 72.6 g/100 mL (100 °C) <hr> ''hexahydrate'' <br> 157 g/100 mL (20 °C)		| Solubility = {{ubl|Anhydrous:|52.9 g/(100 mL) (0 °C)|54.3 g/(100 mL) (20&nbsp;°C)|72.6 g/(100 mL) (100&nbsp;°C)}}
	| Solubility1 = 7.4 g/100 mL (30 °C)		| Solubility1 = 7.4 g/(100 mL) (30&nbsp;°C)
	| Solvent1 = ethanol		| Solvent1 = ethanol
			| SolubleOther = slightly soluble in ], ]
	| LogP =		| LogP =
	| HenryConstant =		| HenryConstant =
	| RefractIndex = 1.675 (anhydrous) <br> 1.569 (hexahydrate)		| RefractIndex = 1.675 (anhydrous) <br /> 1.569 (hexahydrate)
			| MagSus = −47.4·10<sup>−6</sup> cm<sup>3</sup>/mol
	}}		}}
	| Section3 = {{Chembox Structure		|Section3={{Chembox Structure
	| CrystalStruct = ]		| CrystalStruct = ]
	| Coordination = (octahedral, 6-coordinate)		| Coordination = (octahedral, 6-coordinate)
	| MolShape =		| MolShape =
	}}		}}
	| Section4 = {{Chembox Thermochemistry		|Section5={{Chembox Thermochemistry
	| DeltaHf =		| DeltaHf = −641.1 kJ/mol
			| DeltaGf = −591.6 kJ/mol
	| Entropy =
			| Entropy = 89.88 J/(mol·K)
	| HeatCapacity =
			| HeatCapacity = 71.09 J/(mol·K)
	}}		}}
	| Section7 = {{Chembox Hazards		|Section6={{Chembox Pharmacology
			| ATCCode_prefix = A12
	| ExternalMSDS =
	| EUClass =		| ATCCode_suffix = CC01
			| ATC_Supplemental = {{ATC|B05|XA11}}
	| EUIndex = Not listed
			}}
			|Section7={{Chembox Hazards
			| ExternalSDS =
	| MainHazards = Irritant		| MainHazards = Irritant
	| NFPA-H =		| NFPA-H = 1
	| NFPA-F =		| NFPA-F = 0
	| NFPA-R =		| NFPA-R = 0
	| NFPA-O =		| NFPA-S =
			| Hazards_ref=<ref>{{cite web |title=Summary of Classification and Labelling |url=https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/93509 |website=echa.europa.eu}}</ref>
	| RPhrases = {{R36}}, {{R37}}, {{R38}}
	| SPhrases = {{S26}}, {{S37}}, {{S39}}		| GHSPictograms = {{GHS07}}
			| GHSSignalWord = Warning
			| HPhrases = {{H-phrases|319|335}}
			| PPhrases = {{P-phrases|}}
	| FlashPt = Non-flammable		| FlashPt = Non-flammable
	| LD50 = 2800 mg/kg<sup>-1</sup> (oral, rat)		| LD50 = 2800 mg/kg (oral, rat)
	| PEL =		| PEL =
	}}		}}
	| Section8 = {{Chembox Related		|Section8={{Chembox Related
	| OtherAnions = ]<br/>]<br/>]		| OtherAnions = {{ubl|]|]|]}}
	| OtherCations = ]<br/>]<br/>]<br/>]<br/>]		| OtherCations = {{ubl|]|]|]|]|]}}
	| OtherFunctn =		| OtherFunction =
	| Function =		| OtherFunction_label =
	| OtherCpds =		| OtherCompounds =
	}}		}}
	}}		}}
	'''Magnesium chloride''' is the name for the ]s with the ]s MgCl<sub>2</sub> and its various ]s MgCl<sub>2</sub>(H<sub>2</sub>O)<sub>x</sub>. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from ] or ]. Magnesium chloride as the natural mineral ] is also extracted (solution mining) out of ancient seabeds; for example, the ] seabed in northwest Europe. ] magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form usually used in prescription oral magnesium supplements.		'''Magnesium chloride''' is an ] with the ] {{chem2|MgCl2|auto=1}}. It forms ] {{chem2|MgCl2*''n''H2O}}, where ''n'' can range from 1 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in nature, have a variety of practical uses. ] magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form most readily available.<ref name = ullmann/>
			==Production==
	==Structure, preparation, and general properties==
			Magnesium chloride can be extracted from ] or ]. In North America, it is produced primarily from ] brine. In the ], it is obtained from the ]. The mineral ] ({{chem2|MgCl2*6H2O}}) is extracted (by solution mining) out of ancient seabeds, for example, the ] seabed in northwest Europe. Some deposits result from high content of magnesium chloride in the primordial ocean.<ref>{{cite journal |author=Hisahiro Ueda and Takazo Shibuya|title=Composition of the Primordial Ocean Just after Its Formation: Constraints from the Reactions between the Primitive Crust and a Strongly Acidic, CO2-Rich Fluid at Elevated Temperatures and Pressures |journal=Minerals |year=2021 |volume=11 |issue=4 |page=389 |publisher=Minerals 2021, 11(4), p. 389|doi=10.3390/min11040389 |bibcode=2021Mine...11..389U |doi-access=free }}</ref> Some magnesium chloride is made from evaporation of seawater.
	MgCl</sub> crystallizes in the ] motif, which features octahedral Mg. A variety of hydrates are known with the formula MgCl</sub>(H<sub>2</sub>O)<sub>x</sub>, and each loses water with increasing temperature: x = 12 (-16.4 °C), 8 (-3.4 °C), 6 (116.7 °C), 4 (181 °C), 2 (ca. 300 °C).<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.</ref> In the hexahydrate, the Mg+</sup> remains ], but is coordinated to six water ]s.<ref>Wells, A. F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.</ref> The thermal dehydration of the hydrates MgCl</sub>(H<sub>2</sub>O)<sub>x</sub> (x = 6, 12) does not occur straightforwardly.<ref>see notes in Rieke, R. D.; Bales, S. E.; Hudnall, P. M.; Burns, T. P.; Poindexter, G S. “Highly Reactive Magnesium for the Preparation of Grignard Reagents: 1-Norbornane Acid” Organic Syntheses, Collected Volume 6, p.845 (1988). http://www.orgsyn.org/orgsyn/pdfs/CV6P0845.pdf</ref>
			In the ], magnesium chloride is regenerated from magnesium hydroxide using ]:
	As suggested by the existence of some hydrates, anhydrous MgCl<sub>2</sub> is a ], although a very weak one.
			:{{chem2|](]) + 2 HCl(]) → MgCl2(]) + 2 ](])}}
	In the ], magnesium chloride is regenerated from magnesium hydroxide using ]:
	:](]) + 2 HCl → MgCl</sub>(aq) + 2 ](])
	It can also be prepared from ] by a similar reaction.		It can also be prepared from ] by a similar reaction.
			==Structure==
	In most of its derivatives, MgCl</sub> forms octahedral complexes. Derivatives with tetrahedral Mg<sub>2+</sup> are less common. Examples include salts of (])<sub>2</sub>MgCl<sub>4</sub> and ]s such as MgCl</sub>(]).<ref>N. N. Greenwood, A. Earnshaw, ''Chemistry of the Elements'', Pergamon Press, 1984.</ref>
			{{chem2|MgCl2}} crystallizes in the ] {{chem2|CdCl2}} motif, which features octahedral Mg centers.
			Several hydrates are known with the formula {{chem2|MgCl2*''n''H2O}}, and each loses water upon heating: ''n'' = 12 (−16.4&nbsp;°C), 8 (−3.4&nbsp;°C), 6 (116.7&nbsp;°C), 4 (181&nbsp;°C), 2 (about 300&nbsp;°C).<ref>Holleman, A. F.; Wiberg, E. ''Inorganic Chemistry'' Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}.</ref> In the hexahydrate, the {{chem2|Mg(2+)}} is also ], being coordinated to six water ]s.<ref>Wells, A. F. (1984) ''Structural Inorganic Chemistry'', Oxford: Clarendon Press. {{ISBN|0-19-855370-6}}.</ref> The octahydrate and the dodecahydrate can be crystallized from water below 298K. As verified by ], these "higher" hydrates also feature <sup>2+</sup> ions.<ref>{{cite journal |doi=10.1107/S0108270113028138 |title=Crystal Structures of Hydrates of Simple Inorganic Salts. I. Water-Rich Magnesium Halide Hydrates MgCl<sub>2</sub>·8H<sub>2</sub>O, MgCl<sub>2</sub>·12H<sub>2</sub>O, MgBr<sub>2</sub>·6H<sub>2</sub>O, MgBr<sub>2</sub>·9H<sub>2</sub>O, MgI<sub>2</sub>·8H<sub>2</sub>O and MgI<sub>2</sub>·9H<sub>2</sub>O |date=2013 |last1=Hennings |first1=Erik |last2=Schmidt |first2=Horst |last3=Voigt |first3=Wolfgang |journal=Acta Crystallographica Section C Crystal Structure Communications |volume=69 |issue=11 |pages=1292–1300 |pmid=24192174 }}</ref> A decahydrate has also been crystallized.<ref>{{cite journal |doi=10.1107/S205252061500027X |title=Crystal structure of magnesium dichloride decahydrate determined by X-ray and neutron diffraction under high pressure |date=2015 |last1=Komatsu |first1=Kazuki |last2=Shinozaki |first2=Ayako |last3=Machida |first3=Shinichi |last4=Matsubayashi |first4=Takuto |last5=Watanabe |first5=Mao |last6=Kagi |first6=Hiroyuki |last7=Sano-Furukawa |first7=Asami |last8=Hattori |first8=Takanori |journal=Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials |volume=71 |issue=Pt 1 |pages=74–80 |pmid=25643718 }}</ref>
			==Preparation, general properties==
			Anhydrous {{chem2|MgCl2}} is produced industrially by heating the ] named hexamminemagnesium dichloride {{chem2|(2+)(Cl−)2}}.<ref name = ullmann/> The thermal dehydration of the hydrates {{chem2|MgCl2*''n''H2O}} (''n'' = 6, 12) does not occur straightforwardly.<ref>See notes in Rieke, R. D.; Bales, S. E.; Hudnall, P. M.; Burns, T. P.; Poindexter, G. S. "Highly Reactive Magnesium for the Preparation of Grignard Reagents: 1-Norbornane Acid", ''Organic Syntheses'', Collected Volume 6, p. 845 (1988). {{cite web |url=http://www.orgsyn.org/orgsyn/pdfs/CV6P0845.pdf |title=Archived copy |access-date=2007-05-10 |url-status=dead |archive-url=https://web.archive.org/web/20070930212159/http://www.orgsyn.org/orgsyn/pdfs/CV6P0845.pdf |archive-date=2007-09-30 }}</ref>
			As suggested by the existence of hydrates, anhydrous {{chem2|MgCl2}} is a ], although a weak one. One derivative is ] tetrachloromagnesate {{chem2|2}}. The ] {{chem2|MgCl2(])}} is another.<ref>N. N. Greenwood, A. Earnshaw, ''Chemistry of the Elements'', Pergamon Press, 1984.</ref> In the ] with the formula {{chem2|MgCl2(])2}}, Mg adopts an octahedral geometry.<ref>{{cite journal |doi=10.1002/chem.201903120|title=Structure–Solubility Relationship of 1,4-Dioxane Complexes of Di(hydrocarbyl)magnesium |year=2019 |last1=Fischer |first1=Reinald |last2=Görls |first2=Helmar |last3=Meisinger |first3=Philippe R. |last4=Suxdorf |first4=Regina |last5=Westerhausen |first5=Matthias |journal=Chemistry – A European Journal |volume=25 |issue=55 |pages=12830–12841 |pmid=31328293 |pmc=7027550 }}</ref> The Lewis acidity of magnesium chloride is reflected in its ], meaning that it attracts moisture from the air to the extent that the solid turns into a liquid.
	==Applications==		==Applications==
			===Precursor to metallic magnesium===
	Magnesium chloride serves as precursor to other magnesium compounds, for example by precipitation:
			Anhydrous {{chem2|MgCl2}} is the main precursor to metallic magnesium. The reduction of {{chem2|Mg(2+)}} into metallic Mg is performed by ] in ].<ref name = ullmann>{{Ullmann | title = Magnesium Compounds | author1 = Margarete Seeger | author2 = Walter Otto | author3 = Wilhelm Flick | author4 = Friedrich Bickelhaupt | author5 = Otto S. Akkerman | doi = 10.1002/14356007.a15_595.pub2}}</ref><ref name="Hill">Hill, Petrucci, McCreary, Perry, ''General Chemistry'', 4th ed., Pearson/Prentice Hall, Upper Saddle River, New Jersey, USA.</ref> As it is also the case for ], an electrolysis in aqueous solution is not possible as the produced metallic magnesium would immediately react with water, or in other words that the water {{chem2|H+}} would be reduced into gaseous {{chem2|H2}} before Mg reduction could occur. So, the direct electrolysis of molten {{chem2|MgCl2}} in the absence of water is required because the reduction potential to obtain Mg is lower than the stability domain of water on an E<sub>h</sub>–pH diagram (]).
	:MgCl</sub>(]) + ](aq) → ](]) + ](aq)
			:{{chem2|MgCl2 → Mg + Cl2}}
			The production of metallic magnesium at the ] (reduction reaction) is accompanied by the oxidation of the chloride anions at the ] with release of gaseous ]. This process is developed at a large industrial scale.
			=== {{anchor|Use in dust and erosion control}} Dust and erosion control ===
	It can be ] to give ] metal:<ref name="Hill">Hill, Petrucci, McCreary, Perry, "General Chemistry", 4th ed., Pearson/Prentice Hall, Upper Saddle River, New Jersey, USA.</ref>
			Magnesium chloride is one of many substances used for dust control, ], and ] mitigation.<ref name="fs.fed.us">{{cite web |url=http://www.fs.fed.us/eng/pubs/html/99771207/99771207.html#EI |title=Dust Palliative Selection and Application Guide |publisher=Fs.fed.us |access-date=2017-10-18}}</ref> When magnesium chloride is applied to roads and bare soil areas, both positive and negative performance issues occur which are related to many application factors.<ref name="nrcs.usda.gov">{{Cite web |title=FSE Documents |url=https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1043546.pdf |url-status=dead |archive-url=https://web.archive.org/web/20221016220324/https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1043546.pdf |archive-date=2022-10-16 |website=www.nrcs.usda.gov}}</ref>
	:MgCl</sub>(]) → Mg(]) + Cl</sub>(])
	This process is practiced on a substantial scale.
			===Catalysis===
	Magnesium chloride is used for a variety of other applications besides the production of ]: the manufacture of ], ], ], ]s and ] brine,<ref name="Hill" /> and dust and erosion control. Mixed with hydrated magnesium oxide, magnesium chloride forms a hard material called ].
			], used commercially to produce ]s, often contain {{chem2|MgCl2}} as a ].<ref>{{cite book|chapter=Commercially Available Metal Alkyls and Their Use in Polyolefin Catalysts|editor=Ray Hoff |editor2=Robert T. Mathers|author=Dennis B. Malpass|doi=10.1002/9780470504437.ch1|year=2010|publisher= John Wiley & Sons, Inc.|title= Handbook of Transition Metal Polymerization Catalysts|pages=1–28|isbn=9780470504437}}</ref> The introduction of {{chem2|MgCl2}} supports increases the activity of traditional catalysts and allowed the development of highly stereospecific catalysts for the production of ].<ref>{{cite journal |title=The Discovery and Progress of MgCl<sub>2</sub>-Supported TiCl<sub>4</sub> Catalysts |author=Norio Kashiwa |doi=10.1002/pola.10962 |journal=Journal of Polymer Science A |volume=42 |issue=1 |year=2004 |pages=1–8|bibcode=2004JPoSA..42....1K }}</ref>
			Magnesium chloride is also a ] catalyst in ]s.<ref>{{cite journal |doi=10.1021/ja0119548|title=Diastereoselective Magnesium Halide-Catalyzed anti-Aldol Reactions of Chiral N-Acyloxazolidinones |year=2002 |last1=Evans |first1=David A. |last2=Tedrow |first2=Jason S. |last3=Shaw |first3=Jared T. |last4=Downey |first4=C. Wade |journal=Journal of the American Chemical Society |volume=124 |issue=3 |pages=392–393 |pmid=11792206 }}</ref>
	Magnesium ion Mg<sup>2+</sup> (usually added as the chloride) is an important component in the ], a procedure used to amplify DNA fragments. It is generally used in experimental biology whenever RNA and DNA and their enzymes are to function ], since Mg<sup>2+</sup> is a necessary associate ion for ]s in biology, such as ATP.
			=== {{anchor|Use in ice control}} Ice control ===
	Magnesium chloride is also used in several medical and topical (skin related) applications. It has been used in pills as supplemental sources of magnesium, where it serves as a soluble compound which is not as laxative as ], and more bioavailable than ] and ], since it does not require stomach acid to produce soluble Mg<sup>2+</sup> ion. It can also be used as an effective anaesthetic for cephalopods, some species of crustaceans,<ref>http://webs.lander.edu/rsfox/invertebrates/homarus.html</ref> and several species of bivalve, including oysters.<ref>Culloty, S.C. & Mukahy, M.F. 1992. An evaluation of anaesthetics for ''Ostrea edulis'' (L.). Aquaculture. '''107''': 249-252.</ref>
			{{Main article|Road salt}}
			]
			Magnesium chloride is used for low-temperature de-icing of ]s, ]s, and ]s. When highways are treacherous due to icy conditions, magnesium chloride is applied to help prevent ice from bonding to the pavement, allowing ] plows to clear treated roads more efficiently.
	===Culinary use===
	Magnesium chloride (]<ref name=ceua>{{cite web
	| last = ]
	| first =
	| authorlink =
	| coauthors =
	| title = Current EU approved additives and their E Numbers
	| work =
	| publisher =
	| date =
	| url = http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist
	| doi =
	| accessdate = 22 March 2010
	}}</ref>) is an important ] used in the preparation of ] from ]. In Japan it is sold as ''nigari'' (], derived from the Japanese word for "bitter"), a white powder produced from seawater after the ] has been removed, and the water evaporated. In China it is called ''lushui'' (]). ''Nigari'' or ''lushui'' consists mostly of magnesium chloride, with some ] and other trace elements. It is also an ingredient in baby formula milk.
			For the purpose of preventing ice from forming on pavement, magnesium chloride is applied in three ways: anti-icing, which involves spreading it on roads to prevent snow from sticking and forming; prewetting, which means a liquid formulation of magnesium chloride is sprayed directly onto salt as it is being spread onto roadway pavement, wetting the salt so that it sticks to the road; and pretreating, when magnesium chloride and salt are mixed together before they are loaded onto trucks and spread onto paved roads. ] damages concrete twice as fast as magnesium chloride.<ref>Jain, J., Olek, J., Janusz, A., and Jozwiak-Niedzwiedzka, D., "Effects of Deicing Salt Solutions on Physical Properties of Pavement Concretes", Transportation Research Record: Journal of the Transportation Research Board, No. 2290, Transportation Research Board of the National Academies, Washington, D.C., 2012, pp. 69-75. {{doi|10.3141/2290-09}}.</ref> The amount of magnesium chloride is supposed to be controlled when it is used for de-icing as it may cause pollution to the environment.<ref>{{Cite journal|last1=Dai|first1=H.L.|last2=Zhang|first2=K.L.|last3=Xu|first3=X.L.|last4=Yu|first4=H.Y.|date=2012|title=Evaluation on the Effects of Deicing Chemicals on Soil and Water Environment|journal=Procedia Environmental Sciences|language=en|volume=13|pages=2122–2130|doi=10.1016/j.proenv.2012.01.201|doi-access=free|bibcode=2012PrEnS..13.2122D }}</ref>
	===Use as an anti-icer===
	]]A number of state highway departments throughout the United States have decreased the use of ] and sand on roadways and have increased the use of solutions of magnesium chloride (often called "liquid magnesium chloride") as a de-icer or anti-icer. Magnesium chloride is much less toxic to plant life surrounding highways and airports, and is less corrosive to concrete and steel (and other iron alloys) than sodium chloride. The liquid magnesium chloride is sprayed on dry pavement (tarmac) prior to precipitation or wet pavement prior to freezing temperatures in the winter months to prevent snow and ice from adhering and bonding to the roadway. The application of anti-icers is utilized in an effort to improve highway safety. Magnesium chloride is also sold in crystal form for household and business use to de-ice sidewalks and driveways. In these applications, the compound is applied after precipitation has fallen or ice has formed, instead of previously.
			=== {{anchor|Nutritional supplement}} Nutrition and medicine ===
	The use of this compound seems to show an improvement in driving conditions during and after freezing precipitation, but it can damage electric utilities. This occurs in two ways: contamination of insulators, causing tracking and arcing across them, and corrosion of steel and ] poles and pole hardware.
			Magnesium chloride is used in ] and ]. The hexahydrate is sometimes advertised as "]".
			=== {{anchor|Culinary use}} Cuisine ===
	===Use in dust and erosion control===
			Magnesium chloride (]<ref name=ceua>{{cite web
	Road departments and private industry may apply liquid or powdered magnesium chloride to control dust and erosion on unimproved (dirt or gravel) roads and dusty job sites such as quarries. Its ] makes it absorb moisture from the air, controlling the number of small particles which become airborne. Owners of indoor arenas (e.g. for horse riding) may apply magnesium chloride to sand or other floor materials to control dust.
			| last = Food Standard Agency
			| author-link = Food Standard Agency
			| title = Current EU approved additives and their E Numbers
			| url = http://www.food.gov.uk/safereating/chemsafe/additivesbranch/enumberlist
			| access-date = 22 March 2010
			}}</ref>) is an important ] used in the preparation of ] from ].
			In Japan it is sold as '']'' (], derived from the Japanese word for "bitter"), a white powder produced from ] after the ] has been removed, and the water evaporated. In China, it is called ''lushui'' (]).
	===Use in hydrogen storage===
	Magnesium chloride has shown promise as a storage material for ]. ], which is rich in hydrogen atoms, is used as an intermediate storage material. Ammonia can be effectively absorbed onto solid magnesium chloride, forming Mg(NH<sub>3</sub>)<sub>6</sub>Cl</sub>. Ammonia is released by mild heat, and is then passed through a catalyst to give hydrogen gas.
			Nigari or Iushui is, in fact, natural magnesium chloride, meaning that it is not completely refined (it contains up to 5% ] and various minerals). The crystals originate from lakes in the Chinese province of ], to be then reworked in Japan.
	===Medical and veterinary use===
	Medically-prescribed magnesium supplements such as Slo-Mag and Mag-SR contain magnesium chloride which is slowly released from a matrix. However, since magnesium is absorbed by the body in ionic form (after the salt dissolves in water) such supplements have no advantage over any soluble magnesium salt (for example, ] or ]).
			=== Gardening and horticulture ===
	One veterinary study in 1989 indicated some effectiveness against tumors when magnesium chloride was used as a feed additive.<ref></ref>
			Because magnesium is a mobile nutrient, magnesium chloride can be effectively used as a substitute for ] (Epsom salt) to help correct magnesium deficiency in plants via ]. The recommended dose of magnesium chloride is smaller than the recommended dose of magnesium sulfate (20 g/L).<ref>{{cite journal |title=Comparison of Magnesium Sulfate and THIS Mg Chelate Foliar Sprays |journal=Canadian Journal of Plant Science |date=January 1985 |doi=10.4141/cjps85-018 }}</ref> This is due primarily to the chlorine present in magnesium chloride, which can easily reach toxic levels if over-applied or applied too often.<ref>{{cite web |url=http://www.ext.colostate.edu/pubs/garden/07425.html |title=Magnesium Chloride Toxicity in Trees |publisher=Ext.colostate.edu |access-date=2017-10-18 |archive-date=2009-01-15 |archive-url=https://web.archive.org/web/20090115223000/http://www.ext.colostate.edu/pubs/garden/07425.html |url-status=dead }}</ref>
			It has been found that higher concentrations of magnesium in ] and some ] plants can make them more susceptible to disease caused by infection of the bacterium '']'', since magnesium is essential for bacterial growth.<ref>{{cite web |url=http://www.apsnet.org/publications/plantdisease/backissues/Documents/1983Articles/PlantDisease67n06_623.pdf |title=Effect of Foliar and Soil Magnesium Application on Bacterial Leaf Spot of Peppers |access-date=2017-10-18}}</ref>
	=== Experimental antilipid effects in animals ===
			=== Wastewater treatment ===
	In a recent experiment with mice, MgCl</sub> fortification of drinking water reduced cholesterol and triglyceride levels, although overall plasma lipid levels were similar at the beginning and the end of the study.<ref></ref>
			It is used to supply the magnesium necessary to precipitate phosphorus in the form of struvite from agricultural waste<ref>{{cite journal |last1=BURNS |first1=R.T. |title=Laboratory and ''In-Situ'' Reductions of Soluble Phosphorus in Swine Waste Slurries |journal=Environmental Technology |date=15 January 2001 |volume=22 |issue=11 |pages=1273–1278 |doi=10.1080/09593332208618190 |pmid=11804348 |bibcode=2001EnvTe..22.1273B |url=http://www.stormwater.ucf.edu/chemicaltreatment/documents/Burns%20et%20al.,%202001.pdf |archive-url=https://web.archive.org/web/20120327181220/http://www.stormwater.ucf.edu/chemicaltreatment/documents/Burns%20et%20al.,%202001.pdf |access-date=30 December 2023|archive-date=2012-03-27 }}</ref> as well as human urine.
			==Occurrence==
	===Marine aquarium use===
			]
	Magnesium in natural seawater values are between 1250&nbsp;mg/L and 1350&nbsp;mg/L. Magnesium helps to stabilize the correct combination of calcium, alkalinity, and pH values. Severely low values of magnesium (900&nbsp;mg/L or below) can cause low pH values and an inability to maintain proper alkalinity and calcium values. If levels of magnesium become too low, coral growth ceases; decline of coral health follows. Carbonates and calcium are essential for all growth of corals, coralline algae, clams, and invertebrates. Maintaining the correct magnesium values is very important and is indirectly responsible for coral and coralline algae growth by making it possible to maintain correct calcium, alkalinity, and pH values. Magnesium can be depleted by mangrove plants and the use of excessive Kalkwasser or by going beyond natural calcium, alkalinity, and pH values.<ref>http://www.advancedaquarist.com/issues/oct2003/chem.htm</ref>
			Magnesium concentrations in natural ] are between 1250 and 1350&nbsp;mg/L, around 3.7% of the total seawater mineral content. ] minerals contain a significantly higher magnesium chloride ratio, 50.8%. Carbonates and calcium{{clarification needed|reason=which carbonates and calcium in what form?|date=June 2022}} are essential for all growth of ]s, ], ]s, and ]s. Magnesium can be depleted by ] plants and the use of excessive ] or by going beyond natural calcium, ], and ] values.<ref>{{cite web |url=http://www.advancedaquarist.com/issues/oct2003/chem.htm |title=Aquarium Chemistry: Magnesium In Reef Aquaria — Advanced Aquarist &#124; Aquarist Magazine and Blog |publisher=Advancedaquarist.com |date=2003-10-15 |access-date=2013-01-17}}</ref> The most common mineral form of magnesium chloride is its hexahydrate, bischofite.<ref>{{Cite web |title=Bischofite: Mineral information, data and localities |url=https://www.mindat.org/min-681.html |website=mindat.org}}</ref><ref name="ima-mineralogy.org">{{Cite web |date=21 March 2011 |title=List of Minerals |url=https://www.ima-mineralogy.org/Minlist.htm |website=International Mineralogical Association}}</ref> Anhydrous compound occurs very rarely, as chloromagnesite.<ref name="ima-mineralogy.org"/> Magnesium chloride-hydroxides, korshunovskite and nepskoeite, are also very rare.<ref>{{Cite web |title=Korshunovskite: Mineral information, data and localities |url=https://www.mindat.org/min-2256.html |website=mindat.org}}</ref><ref>{{Cite web |title=Nepskoeite: Mineral information, data and localities |url=https://www.mindat.org/min-7189.html |website=mindat.org}}</ref><ref name="ima-mineralogy.org"/>
	== Toxicology ==		== Toxicology ==
	Magnesium ions are bitter-tasting, and magnesium chloride solutions are bitter in varying degrees, depending on the concentration of magnesium.		Magnesium ions are bitter-tasting, and magnesium chloride solutions are bitter in varying degrees, depending on the concentration.
	Magnesium toxicity from magnesium salts is rare in healthy individuals with a normal diet, because excess magnesium is readily excreted in urine by the ]. A few cases of oral magnesium toxicity have been described in persons with normal renal function ingesting large amounts of magnesium salts, but it is rare. If a large amount of magnesium chloride is eaten, it will have effects similar to ], causing diarrhea, although the sulfate also contributes to the laxative effect in magnesium sulfate, so the effect from the chloride is not as severe.		Magnesium toxicity from magnesium salts is rare in healthy individuals with a normal diet, because excess magnesium is readily excreted in ] by the ]. A few cases of ] magnesium toxicity have been described in persons with normal renal function ingesting large amounts of magnesium salts, but it is rare. If a large amount of magnesium chloride is eaten, it will have effects similar to ], causing diarrhea, although the sulfate also contributes to the laxative effect in magnesium sulfate, so the effect from the chloride is not as severe.
			=== Plant toxicity ===
			Chloride ({{chem2|Cl−}}) and magnesium ({{chem2|Mg(2+)}}) are both essential nutrients important for normal plant growth. Too much of either nutrient may harm a plant, although foliar chloride concentrations are more strongly related with foliar damage than magnesium. High concentrations of {{chem2|MgCl2}} ions in the soil may be toxic or change water relationships such that the plant cannot easily accumulate water and nutrients. Once inside the plant, chloride moves through the water-conducting system and accumulates at the margins of leaves or needles, where dieback occurs first. Leaves are weakened or killed, which can lead to the death of the tree.<ref name="colostate1">{{cite web |url=http://www.ext.colostate.edu/pubs/garden/07425.html |title=Publications – ExtensionExtension |publisher=Ext.colostate.edu |access-date=2017-10-18 |archive-url=https://web.archive.org/web/20150924005210/http://www.ext.colostate.edu/pubs/garden/07425.html |archive-date=2015-09-24 |url-status=dead }}</ref>
	== See also ==		== See also ==
	* ]		* ]
			* ]
	== Notes & references ==		== Notes and references ==
			;Notes
	<div style="font-size:88%;">
			{{Reflist|30em}}
	<references />
			;References
	</div>
	* ''Handbook of Chemistry and Physics'', 71st edition, CRC Press, Ann Arbor, Michigan, 1990.		* ''Handbook of Chemistry and Physics'', 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
	== External links ==		== External links ==
	*		*
	*		*
	{{Magnesium compounds}}		{{Magnesium compounds}}
			{{Chlorides}}
			{{Mineral supplements}}
	]		]
	]		]
	]		]
	]		]
			]
			]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]
	]