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|Section2= |Section3= |Section5= |Section6= |Section7= |Section8= }} Magnesium chloride is the name for the chemical compound with the formula MgCl2 and its various hydrates MgCl2(H2O)x. These salts are typical ionic halides, being highly soluble in water. The hydrated magnesium chloride can be extracted from brine or sea water. In North America, magnesium chloride is produced primarily from Great Salt Lake brine. It is extracted in a similar process from the Dead Sea in the Jordan valley. Magnesium chloride, as the natural mineral bischofite, is also extracted (via solution mining) out of ancient seabeds; for example, the Zechstein seabed in northwest Europe. Some magnesium chloride is made from solar evaporation of seawater. Anhydrous 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. ==Structure, preparation, and general properties== MgCl2 crystallizes in the cadmium chloride motif, which features octahedral Mg. A variety of hydrates are known with the formula MgCl2(H2O)x, 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).〔Holleman, A. F.; Wiberg, E. ''Inorganic Chemistry'' Academic Press: San Diego, 2001. ISBN 0-12-352651-5.〕 In the hexahydrate, the Mg2+ remains octahedral, but is coordinated to six water ligands.〔Wells, A. F. (1984) ''Structural Inorganic Chemistry'', Oxford: Clarendon Press. ISBN 0-19-855370-6.〕 The thermal dehydration of the hydrates MgCl2(H2O)x (x = 6, 12) does not occur straightforwardly.〔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〕 As suggested by the existence of some hydrates, anhydrous MgCl2 is a Lewis acid, although a very weak one. In the Dow process, magnesium chloride is regenerated from magnesium hydroxide using hydrochloric acid: :Mg(OH)2(s) + 2 HCl → MgCl2(aq) + 2 H2O(l) It can also be prepared from magnesium carbonate by a similar reaction. In most of its derivatives, MgCl2 forms octahedral complexes. Derivatives with tetrahedral Mg2+ are less common. Examples include salts of (tetraethylammonium)2MgCl4 and adducts such as MgCl(TMEDA).〔N. N. Greenwood, A. Earnshaw, ''Chemistry of the Elements'', Pergamon Press, 1984.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Magnesium chloride」の詳細全文を読む スポンサード リンク
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