粉状白钨酸研究(ⅩⅠⅩ)——聚乙烯醇水溶液中十聚钨酸的稳定性和光化学还原

Studies on White Powdery Tungstic Acid(ⅩⅠⅩ) Stability and Photochemistry of Decatungstic Acid in Aqueous Solution Containing Polyvinyl Alcohol

粉状白钨酸在含聚乙烯醇的水溶液中能够形成十聚钨酸，通过紫外－可见吸收光谱、顺磁共振、ｐＨ滴定及五价钨的测定对十聚钨酸的稳定性和光致变色性质进行了研究，结果表明，十聚钨酸的还原程度与溶液的酸度有关，在较高的ｐＨ条件下形成单电子还原物种，而在较低的ｐＨ条件下则主要形成双电子还原物种．

Decatungstic acid can be formed by the reaction of white powdery tungstic acid in aqueous solution containing polyvinyl alcohol. The stability and photochromism of decatungstic acid in homogeneous system have been studied through UV Vis spectra, ESR, pH titration and W(Ⅴ) determination. The results show that the reduction degree of decatungstate anion corresponds to the acidity of the solution. One electron reduced form is produced mainly at high pH value while two electron reduced form mainly at low pH value.