溶液中钪与草酸离子的配位作用

Coordination of Scandium with Oxalate Ions in Aqueous Medium

提钪工艺中常使草酸钪溶于过量草酸铵溶液中。但文献中有关钪与草酸离子配位作用的报导甚少。等用分光光度法测定了ScC_(2)O4^(+)配离子的稳定常数,而J·Stary则用分配法测定了SC(C_(2)O_(4)_(3))^(3-)配离子的稳定常数,这些工作都没有对溶液中可能生成各级配离子进行研究。

The solubilities of scandium-oxalate in solutions of various concentration of ammonium oxalate and ammonium perchlorate(the latter is to maintain a constant ionic strength of 2)were measured at 25℃.The existence of complexes ions[ScC_(2)O_(4)]%[Sc(C_(2)O_(4))_(2)]and[Sc(C_(2)O_(4))_(2)]^(3-)have been revealed from the treatment of experimented data by useing of qraphic extrapolation.The solubility product of scandium oxalate was also calculated to be 1.22×10-22(μ=2,pH=1).The succesive stability constants of the complexes formed were calculated by two ways:relaxation method and a least-squares technique on a computer.The results are as follows:β_(1)=1.94×108;β_(2)=5.5×10^(15);β_(5)=2.0×10^(16).