Kameda Yasuo, Maeda Shunya, Amo Yuko, Usuki Takeshi, Ikeda Kazutaka, Otomo Toshiya
Department of Material and Biological Chemistry, Faculty of Science, Yamagata University , Yamagata, Yamagata 990-8560, Japan.
Institute of Material Structure Science, KEK , Tsukuba, Ibaraki 305-080, Japan.
J Phys Chem B. 2018 Feb 8;122(5):1695-1701. doi: 10.1021/acs.jpcb.7b12218. Epub 2018 Jan 26.
Neutron diffraction measurements have been carried out for Li/Li isotopically substituted aqueous 1.0 mol % (0.5 mol/kg) LiCl and 1.1 mol % (0.56 mol/kg) LiClO solutions in DO to obtain structural insight concerning hydration structure of Li in more dilute electrolyte solutions. The first-order difference function, Δ(Q), was analyzed by means of the least squares fitting procedure to obtain short-range structural parameters around the Li. It was revealed that the nearest neighbor Li···O(DO) distance, r, and the coordination number, n, for the aqueous 1.0 mol % LiCl solution are 2.01 ± 0.02 Å and 5.9 ± 0.1, respectively. The values, r = 1.97 ± 0.02 Å and n = 6.1 ± 0.1, are obtained for aqueous 1.1 mol % LiClO solution. These results indicate that the hydration number of Li in a dilute solution is close to 6, which is much larger than 4, which has long been believed. A possible explanation is that the hydration number of Li varies with the solute concentration.
已对溶解于重水（DO）中的锂/锂同位素取代的1.0 mol%（0.5 mol/kg）LiCl水溶液和1.1 mol%（0.56 mol/kg）LiClO水溶液进行了中子衍射测量，以深入了解更稀电解质溶液中锂的水合结构。通过最小二乘法拟合程序分析一阶差分函数Δ(Q)，以获得锂周围的短程结构参数。结果表明，对于1.0 mol% LiCl水溶液，最近邻Li···O(DO)距离r和配位数n分别为2.01±0.02 Å和5.9±0.1。对于1.1 mol% LiClO水溶液，得到的值为r = 1.97±0.02 Å和n = 6.1±0.1。这些结果表明，稀溶液中锂的水合数接近6，这比长期以来认为的4大得多。一种可能的解释是，锂的水合数随溶质浓度而变化。
