Magnesium chloride: Difference between revisions

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Hello My name is Ancksunamun and I am looking for information to help me with this project. I need information on Magnesium Chloride.

{| align="right" width="300" border="1" cellspacing="0" cellpadding="3" style="margin: 0 0 0 0.5em; background: #FFFFFF; border-collapse: collapse"

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| align="center" colspan="2" | [[Image:Magnesium_chloride.jpg|200px|{{PAGENAME}}]] <br/> '' Magnesium chloride hexahydrate ''

|-

| align="center" colspan="2" | '''[[systematic name|IUPAC]] name''' <br/> Magnesium chloride

|- style="border-top: 3px solid gray"

! bgcolor="#ffddaa" colspan="2" | General

|-

| bgcolor="#ffeedd" | [[Molecular formula]]

| MgCl₂

|-

| bgcolor="#ffeedd" | [[Molecular weight]]

| 95.22 [[atomic mass unit|amu]] (anhydrous)

203.31 [[atomic mass unit|amu]] (hexahydrate)

|-

| bgcolor="#ffeedd" | Appearance

| white or colourless crystalline solid

|-

| bgcolor="#ffeedd" | [[CAS number]]

| [7786-30-3] (anhydrous)

[7791-18-6] (hexahydrate)

|-

| bgcolor="#ffeedd" | [[MSDS]]

| [[Wikisource:{{PAGENAME}} MSDS|{{PAGENAME}} MSDS]]

|-

! bgcolor="#ffeedd" colspan="2" | Other names

|-

| colspan="2" |

* '''Magnesium(II) chloride'''

|-

! bgcolor="#ffddaa" colspan="2" | Bulk Properties

|-

| bgcolor="#ffeedd" | [[Density]]

| 2.32 [[gram|g]]/[[centimetre|cm]]³ (anhydrous)

1.56 [[gram|g]]/[[centimetre|cm]]³ (hexahydrate)

|-

| bgcolor="#ffeedd" | [[Solubility]]

| [[water]]: 54.2 [[gram|g]]/100 [[centimetre|cm]]³ (20 &deg;[[celsius|C]])

[[ethanol]]: 7.4 [[gram|g]]/100 [[centimetre|cm]]³ (30 &deg;[[celsius|C]])

|-

| bgcolor="#ffeedd" | [[Melting point]]

| 714 &deg;[[celsius|C]] (987 [[kelvin|K]])

|-

| bgcolor="#ffeedd" | [[Boiling point]]

| 1412 &deg;[[celsius|C]] (1685 [[kelvin|K]])

|-

| bgcolor="#ffeedd" | Hazards:

| Irritant

|-

! bgcolor="#ffddaa" colspan="2" | Structure

|-

| bgcolor="#ffeedd" | [[Coordination geometry]]

| (octahedral, 6-coordinate?)

|-

| bgcolor="#ffeedd" | [[Crystal structure]]

| [[Cadmium_chloride#Crystal_structure|CdCl₂]]

|-

| bgcolor="#ffeedd" | [[Hydrate]]s

| hexahydrate

|-

! bgcolor="#ffddaa" colspan="2" | Related Compounds

|-

| bgcolor="#ffeedd" | [[magnesium fluoride]]

[[magnesium bromide]]

[[magnesium iodide]]

| [[beryllium chloride]]

[[calcium chloride]]

|-

|}

'''Magnesium chloride''' is composed of [[magnesium]] and [[chlorine]] and is a typical ionic halide, being highly polar and soluble in water. It is a weak [[Lewis acid]], so not surprisingly the hexahydrate can undergo partial [[hydrolysis]] when heated. Magnesium chloride can be extracted from [[brine]] or [[sea water]], and is a commonly used source of magnesium metal, which can be extracted from MgCl₂ using [[electrolysis]]. In 1990, US production was around one million [[tonne]]s, with a bulk price around $180 per tonne.

== Chemical properties ==

'''Magnesium chloride''' can serve as a source of magnesium compounds, for example by precipitation:

MgCl₂([[aqueous|aq]]) + [[calcium hydroxide|Ca(OH)₂]]([[aqueous|aq]]) &rarr; [[magnesium hydroxide|Mg(OH)₂]]([[solid|s]]) + [[calcium chloride|CaCl₂]]([[aqueous|aq]])

It can be [[electrolysis|electrolysed]] to give [[magnesium]] metal:

MgCl₂([[liquid|l]]) &rarr; Mg([[liquid|l]]) + Cl₂([[gas|g]])

Both of these reactions are used in the Dow process for production of metallic [[magnesium]].^[3] Unlike [[aluminium chloride]], hydrated MgCl₂ can be dehydrated without hydrolysis (under certain conditions). This allows anhydrous MgCl₂ to be used as a cheap source of the metal via electrolysis.

Magnesium chloride can also act as a weak [[Lewis acid]], and salts containing the MgCl₄^2- are known, though rare.^[2]

==Preparation==

In the Dow process, magnesium chloride is regenerated from [[magnesium hydroxide]] using [[hydrochloric acid]]:

[[magnesium hydroxide|Mg(OH)₂]]([[solid|s]]) + 2 [[hydrochloric acid|HCl]] &rarr; MgCl₂(aq) + 2 [[water|H₂O]]([[liquid|l]])

It may also be prepared from [[magnesium carbonate]] by a similar reaction.

== Uses ==

'''Magnesium chloride''' is used for a variety of applications, besides the manufacture of [[magnesium]] via the Dow process discussed above. It is used in the manufacture of [[textiles]], [[paper]], [[fireproofing agents]], [[cement]]s and [[refrigeration]] brine.^[3]

===Culinary use===

Magnesium chloride is an important coagulant used in the preparation of [[tofu]] from [[soy milk]]. In Japan it is sold as ''nigari'' (the term is derived from the Japanese word for "bitter"), a white powder produced from seawater after the [[sodium chloride]] has been removed, and the water evaporated. Nigari consists mostly of magnesium chloride, with some [[magnesium sulfate]] and other trace elements.

===Use as an anti-icer===

A number of state highway departments throughout the United States have decreased the use of [[rock salt]] and sand on roadways and have increased the use of liquid magnesium chloride as a de-icer or anti-icer. 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. The use of this product seems to show an improvement in driving conditions during and after freezing precipitation yet it seems to be negatively affecting electric utilities.

Two main issues have been raised regarding the anti-icer magnesium chloride as it relates to electric utilities: contamination of insulators causing tracking and arcing across them, and corrosion of steel and [[aluminium]] poles and pole hardware.

===Use in Hydrogen Storage===

Magnesium chloride has shown promise as a storage material for [[hydrogen]]. [[Ammonia]], which is rich in hydrogen atoms, is used as an intermediate storage material. Ammonia can be effectively absorbed to solid Magnesium chloride, forming Mg(NH3)6Cl2. Ammonia is released by mild heat, and is then passed through a catalyst to give hydrogen gas.

== Precautions ==

Irritant. Wear gloves and goggles. For more details see a [http://www.jtbaker.com/msds/englishhtml/m0156.htm Baker MSDS].

== Suppliers/Manufacturers ==

*[http://www.emdchemicals.com/nsearch/searchcatalog.aspx?searchfor=magnesium+chloride&Division=0&SearchType=Product EMD Chemicals]

*[http://www.sigmaaldrich.com Aldrich]

*[http://www.alfa.com/alf/index.htm Alfa]

*[http://www.vwr.com/index.htm VWR]

*[https://www1.fishersci.com/index.jsp Fisher]

== External links ==

* [http://www.usda.gov/rus/electric/engineering/2001/magnesium_chloride.htm Magnesium Chloride as a De-Icing Agent]

[[da:Magnesiumchlorid]]

[[de:Magnesiumchlorid]]

[[ja:&#22633;&#21270;&#12510;&#12464;&#12493;&#12471;&#12454;&#12512;]]

[[pl:Chlorek magnezu]]

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[[Category:Chlorides]][[Category:Magnesium compounds]]

[[Category:Metal halides]]

== References ==

# ''Handbook of Chemistry and Physics'', 71st edition, CRC Press, Ann Arbor, Michigan, 1990.

# N. N. Greenwood, A. Earnshaw, ''Chemistry of the Elements'', Pergamon Press, 1984.

# Hill, Petrucci, McCreary, Perry, "General Chemistry", 4th ed., Pearson/Prentice Hall, Upper Saddle River, New Jersey, USA.