仲钨酸钠的热分解研究

制备了仲钨酸钠Na（10）H2W（12）O（42）·27H2O，用X射线衍射、Raman光谱及化学分析进行了表征．热分析的研究表明：该化合物热分解过程包括六个步骤．其中前四步为脱水步骤，温度分别为331，353，403及588K左右，而失水数分别为10H2O，9H2O，5H2O及4H2O；第五步可能为中间产物的相转变，温度为691K左右，第六步生成Na2W2O7和Na2W4O（13）的混合物，温度为733K左右．前五步中每一步的产物在标题化合物馆和溶液的气相中平衡处理之后，又都能得到标题化合物．

Study on Thermal Decomposition of Sodium Paratungstate Na_(10)H_2W_(12)O_(42) 27H_2O

In this paper, the preparation of sodium paratungstate Na10H2W12O42' 27H2O(SPTB )and its characterization by X-ray diffraction, Raman spectrum and chemical analysis have beenstudied. The thermal decomposition of SPTB has been also studied.The overall mechanism ofdecomposition involves seven separate stages.The first four stages are dehydration stages, whichoccur at about 331K, 353K, 403K and 588K respectively, and which correspond to the loss of10H2O, 9H2O, 5H2O and 4H2O respectively. The fifth stage, which occurs at about 691K. is aphase transformation of an intermediate.The sixth stage, which occurs at about 733K, is the for-mation of the mixture of Na2W2O7 and Na2W4O13.The first five stages are all reversible.