Lindqvist-Reis Patric, Muñoz-Páez Adela, Díaz-Moreno Sofia, Pattanaik Sidhartha, Persson Ingmar, Sandström Magnus
Department of Chemistry, Royal Institute of Technology, S-100 44 Stockholm, Sweden, Instituto de Ciencia de Materiales de Sevilla CSIC, University of Sevilla, C/Americo Vespucio s/n, E-41092 Sevilla, Spain, and Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, S-750 07 Uppsala, Sweden.
Inorg Chem. 1998 Dec 28;37(26):6675-6683. doi: 10.1021/ic980750y.
The structure of the hydrated gallium(III), indium(III), and chromium(III) ions has been determined in aqueous perchlorate and nitrate solutions by means of the large-angle X-ray scattering (LAXS) and extended X-ray absorption fine structure (EXAFS) techniques. The EXAFS studies have been performed over a wide concentration range, 0.005-1.0 mol.dm(-)(3) (2.6 mol.dm(-)(3) for chromium(III)), while the LAXS studies are restricted to concentrated solutions, ca. 1.5 mol.dm(-)(3). All three metal ions were found to coordinate six water molecules, each of which are hydrogen bonded to two water molecules in a second hydration sphere. The metal-oxygen bond distance in the first hydration sphere of the gallium(III), indium(III), and chromium(III) ions was determined by LAXS and EXAFS methods to be 1.959(6), 2.131(7), and 1.966(8) Å. The LAXS data gave mean second sphere M.O distances of 4.05(1), 4.13(1), and 4.08(2) Å for the gallium(III), indium(III), and chromium(III) ions, respectively. The perchlorate ion was found to be hydrogen bonded to 4.5(7) water molecules with the O.O distance 3.05(2) Å and Cl.O 3.68(3) Å. Analyses of the Ga, In, and Cr K-edge EXAFS data of the aqueous perchlorate and nitrate solutions showed no influence on the first shell M-O distance by a change of concentration or anion. The minor contribution from the second sphere M.O distance is obscured by multiple scattering within the tightly bonded first shell. EXAFS data for the alum salts CsM(SO(4))(2).12H(2)O, M = Ga or In, showed the M-O bond length of the hexahydrated gallium(III) and indium(III) ions to be 1.957(2) and 2.122(2) Å, respectively.
通过大角度X射线散射（LAXS）和扩展X射线吸收精细结构（EXAFS）技术，已测定了高氯酸盐和硝酸盐水溶液中镓（III）、铟（III）和铬（III）水合离子的结构。EXAFS研究是在0.005 - 1.0 mol·dm⁻³（铬（III）为2.6 mol·dm⁻³）的宽浓度范围内进行的，而LAXS研究仅限于约1.5 mol·dm⁻³的浓溶液。发现所有三种金属离子均与六个水分子配位，每个水分子在第二水合球中与另外两个水分子形成氢键。通过LAXS和EXAFS方法测定，镓（III）、铟（III）和铬（III）离子第一水合球中的金属 - 氧键距离分别为1.959(6)、2.131(7)和1.966(8) Å。LAXS数据给出镓（III）、铟（III）和铬（III）离子第二球M - O平均距离分别为4.05(1)、4.13(1)和4.08(2) Å。发现高氯酸根离子与4.5(7)个水分子形成氢键，O - O距离为3.05(2) Å，Cl - O距离为3.68(3) Å。对高氯酸盐和硝酸盐水溶液中Ga、In和Cr K边EXAFS数据的分析表明，浓度或阴离子的变化对第一壳层M - O距离没有影响。第二球M - O距离的微小贡献被紧密键合的第一壳层内多次散射所掩盖。CsM(SO₄)₂·12H₂O（M = Ga或In）铝盐的EXAFS数据表明，六水合镓（III）和铟（III）离子的M - O键长分别为1.957(2)和2.122(2) Å。
