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|Section2= |Section3=〔http://cameochemicals.noaa.gov/chemical/3829〕 }} Mercury(II) cyanide, also known as mercuric cyanide, is a coordination compound of nitrogen, carbon and mercury. It is a colorless, odorless, toxic white powder with a bitter metallic taste.〔"Hydrargyrum. Mercury. Part 5." http://chestofbooks.com/health/materia-medica-drugs/Manual-Pharmacology/Hydrargyrum-Mercury-Part-5.html (accessed April 1, 2009).〕 It has a melting point of , at which it decomposes and releases toxic mercury fumes. It is highly soluble in polar solvents such as water, alcohol, and ammonia; slightly soluble in ether; and insoluble in benzene and other hydrophobic solvents.〔Kocovsky, P., G. Wang, and V. Sharma. "Mercury(II) Cyanide." ''e-EROS Encyclopedia of Reagents for Organic Synthesis.'' Chichester, UK: John Wiley & Sons, Ltd., 2001. http://www.mrw.interscience.wiley.com/eros/articles/rm034/sect0-fs.html (accessed April 1, 2009).〕 It rapidly decomposes in acid to give off hydrogen cyanide. Samples also decompose when exposed to light, becoming darker in color.〔Brunton, L.T. ''A Text-Book Of Pharmacology, Therapeutics And Materia Medica.'' London: MacMillan & Co., 1885.〕 It reacts vigorously with oxidizing agents; fusion with metal chlorates, perchlorates, nitrates, or nitrites can cause a violent explosion.〔NOAA, Office of Response and Restoration, CAMEO Chemicals. "Chemical Datasheet: Mercuric Cyanide." NOAA. http://cameochemicals.noaa.gov/chemical/3829 (accessed April 2, 2009).〕 ==Molecular and crystal structure== At ambient temperature and ambient pressure, Hg(CN)2 takes the form of tetragonal crystals.〔 These crystals are composed of nearly linear Hg(CN)2 molecules with a C-Hg-C bond angle of 175.0° and an Hg-C-N bond angle of 177.0° (Aylett〔Aylett, B.J. “Mercury (II) Pseudohalides: Cyanide, Thiocyanate, Selenocyanate, Azide, Fulminate.” ''Comprehensive Inorganic Chemistry'' 3:304-306. J.C. Bailar, Harry Julius Emeléus, Sir Ronald Nyholm, and A.F. Trotman-Dickenson, ed. Oxford: Pergamon Press, 1973; distributed by Compendium Publishers (Elmsford, NY), p. 304.〕 gives slightly different values of 189° and 175°, respectively). Raman spectra show that the molecules distort at higher pressures. Between 16-20 kbar, the structure undergoes a phase transition as the Hg(II) center changes from 2- to 4-coordinate as the C''N'' groups bind to neighboring Hg centers forming via Hg-N bonds. The coordination geometry thus changes from tetragonal to tetrahedral, forming a cubic crystal structure, analogous to the structure of Cd(CN)2. Due to the ambidentate nature of the CN ligands, this tetrahedral structure is distorted, but the distortion lessens with increasing pressure until the structure becomes nearly perfectly tetrahedral at >40 kbar.〔Wong, P.T.T. ''J. Chem. Phys''. 1984, 80(12), 5937-41.〕 As in the solid state, aqueous solution, Hg(CN)2 molecules are linear.〔 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「Mercury(II) cyanide」の詳細全文を読む スポンサード リンク
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