胍盐化合物[C(NH_2)_3]_(6.3)K[Nb_(1.3)W_(10.7)O_(40)H_2]·H_2O的合成及性质

通过粉状白钨酸和可溶性铌酸钾水溶液的反应,合成了十二聚系列的钨铌杂多阴离子胍盐化合物C(NH_2)_3]_(6.3)KNb_(1.3)W_(10.7)O_(40)H_2]·H_2O,研究了其水溶液的酸碱稳定性。根据红外、拉曼和紫外光谱、化学性质,认为该化合物可能具有十二聚偏钨酸根阴离子的结构骨架。

SYNTHESIS AND PROPERTIES OF [(NH_2)_2C = NH - H]_(6.3) ?K[Nb_(1.3)W_(10.7)O_(40)H_2]- H2O

The anion of tungstoniobatc was synthesized first time successfully as (NH2)2C = H]6.3 ?KNb1.3W10.7O40H2] H2O by the reaction of soluble potassium noibatc and porous white tungstic acid in aqueous solution and then the anion was precipitated as its guanidinc salt with guanidine nitrate. The structure of the anion may be proposed reasonably to be similar to that of dodccamcric anion of mctatungstatc, resulting from partial substituting of WO6 group in mctatungstate anion by NbO6 group and leading to the formation of tungstoniobate anion according to the extreme similarity of IR and UV spectra of these two different anions. The complex is slightly soluble in water and unstable in alkaline medium while the structure of anion may be considered to keep unchanged in acidic medium according to the spectrophotometrical results.