锌与羟基的配位作用及晶状氢氧化锌的溶度积

COORDINATION OF ZDMC WITH HYDROXO - IONS IN AQUEOUS MEDIUM AND SOLUBILITY PRODUCT FOR e - Zn(OH)_2 CRYSTAL

为对文献[1]报道的ε-Zn（OH）2的溶度积值作更准确的测定,用溶解度法研究了Zn2+与羟基的配位作用,在25℃下测定了ε-Zn（OH）2在不同浓度氢氧化钠溶液中的溶解度（μ=2）.在所研究体系中揭示出存在Zn（OH）+,Zn（OH）20,Zn（OH）3-和Zn（OH）42-配离子.用图解法和松驰法计算出相应配离子的稳定常数相一致,结果为:β1=8.1×104,β2=6.3×1011,β3=3.9×1014,β4=1.2×1018.同时求出了更为准确的ε-Zn（OH）2的溶度积Ksp=10×10-17.

The solubility value of e - Zn(OH)2 crystal in solutions of various concentration of sodium hydroxide and sodium perchlorate (with a constant ionic strength of 2) were measured at 25C . The existence of complexes ions Zn(OH) + , Zn(OH)02, Zn(OH)3- and Zn(OH)2-4 has been revealed from the treatment of experiment data with the help of graphic extrapolation. The successive stability constants of the complexes formed were calculated by two methods: graphic extrapolation and relaxation method respectively. The results are as following: B1 = 8.1 x104, B2 = 6.3x1011,B3 = 3.9x 1014,B4 = 1.2x 1018. The solubility product of e - Zn (OH)2 was also calculated to be 1.0 x 10~17(u = 2.25 C), which corrects the numerical value reported in a previous reference.