|
Mercury polycations are polyatomic cations that contain only mercury atoms. The best known example is the ion, found in mercury(I) (mercurous) compounds. The existence of the metal-metal bond in Hg(I) compounds was established using X-ray studies in 1927〔Wells A.F. (1962) ''Structural Inorganic Chemistry'' 3d edition Oxford Science Publications〕 and Raman spectroscopy in 1934 making it one of the earliest, if not the first, covalent metal-metal bonds to be characterised. Other mercury polycations are the linear and ions,〔 and the triangular ion 〔Terlinguait, Hg4O2Cl2 - ein Mineral mit ungewöhnlichen Hg3-Baueinheiten, K. Brodersen,G. Göbel, G. Liehr, Zeitschrift für anorganische und allgemeine Chemie, 575, 1, 1989, 145 - 153, 〕 and a number of chain〔Alchemists' Gold, Hg2.86 AsF6; An X-Ray Crystallographic Study of A Novel Disordered Mercury Compound Containing Metallically Bonded Infinite Cations, I. David Brown, Brent D. Cutforth, Colin G. Davies, Ronald J. Gillespie, Peter R. Ireland, and John E. Vekris, Can. J. Chem. 52(5): 791-793 (1974),〕 and layer polycations. ==Mercury(I)== The best known polycation of mercury is , in which mercury has a formal oxidation state of +1. The ion was perhaps the first metal-metal bonded species confirmed. The presence of the ion in solution was shown by Ogg in 1898.〔A. Ogg; Zeitschrift Physische Chemie 27, 285 (1898)〕 In 1900, Baker showed the presence of HgCl dimers in the vapour phase.〔Vapour density of dried mercurous chloride, H. Brereton Baker M.A., J. Chem. Soc., Trans., 1900, 77, 646, 〕 The presence of units in the solid state first determined in 1926 using X-Ray diffraction.〔 The presence of the metal-metal bond in solution was confirmed using Raman spectroscopy in 1934.〔 is stable in aqueous solution, where it is in equilibrium with and elemental Hg, with present at around 0.6%.〔 This equilibrium is readily shifted by the addition of an anion which forms an insoluble Hg(II) salt, such as , which causes the Hg(I) salt to completely disproportionate, or by the addition of an anion which forms an insoluble Hg(I) salt, such as , which causes the elemental mercury and Hg2+ to completely recombine into the mercury(I) salt.〔 Minerals that are known that contain the cation include eglestonite.〔Eglestonite, ()3Cl3O2H: Confirmation of the chemical formula by neutron powder diffraction, Mereiter K., Zemann J., Hewatt A.W. American Mineralogist, 77, (1992), 839-842〕 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 polycations」の詳細全文を読む スポンサード リンク
|