Darstellung und Strukturuntersuchung von Polywolframaten Ein Beitrag zur Aufklärung des Parawolframations A / Preparation and Structure Investigation of Polytungstates A Contribution to the Paratungstate A Problem
Darstellung und Strukturuntersuchung von Polywolframaten Ein Beitrag zur Aufklärung des Parawolframations A / Preparation and Structure Investigation of Polytungstates A Contribution to the Paratungstate A Problem
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多钨酸盐 A / 多钨酸盐的制备和结构研究对仲钨酸盐 A 问题的贡献
DOI：
10.1515/znb-1979-0311
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发表时间：
1979
期刊：
影响因子：
--
通讯作者：
E.‐P. Flindt
中科院分区：
文献类型：
--
作者：
J. Fuchs;E.‐P. Flindt
摘要多钨酸盐是由水合钨（VI）氧化物与碱或盐反应，偶尔加入有机溶剂后得到的。使用液氨，产生了迄今未知的二钨酸盐（NH 4）2 W2 O 7。它的红外光谱有几个吸收带，这表明它的结构非常简单。在不同的实验条件下，合成了5个化合物，它们的组成与仲钨酸盐相近，但晶体习性、晶格参数、溶解度和红外光谱各不相同。结构测定表明，其中两个化合物为七钨酸盐，其阴离子W7 O246-与七钼酸盐离子Mo 7 O246-具有相同的结构。通过将它们的拉曼光谱与新鲜酸化的钨酸钠溶液（命名为仲钨酸盐A）的光谱进行比较，可以得出结论，七钨酸盐离子是这种溶液中的主要物种。用X-射线衍射法测定了三丁基铵（5：24）：钨酸盐[（C_4H_9）_3NH]_5H_3W_（12）O_（40）的阴离子结构。钨原子的排列与α-十二钨磷酸根离子（Keggin结构）相同。
Abstract Polytungstates are obtained by the reaction of hydrated tungsten (VI) oxide with bases or salts after occasional addition of organic solvents. With liquid ammonia the as yet unknown ditungstate, (NH4)2W2O7, is produced. Its IR spectrum has few absorption bands suggesting a very simple constitution. Piperidine yields 5 compounds according to varied experimental conditions, which all exhibit approximately paratungstate compositions but different crystal habits, lattice parameters, solubility and IR spectra. Structure determinations indicate that two of these compounds are heptatungstates, the anion of which, W7O246-, has the same structure as the heptamolybdate ion, Mo7O246-. From a comparison of their Raman spectra with the spectrum of a freshly acidified sodium tungstate solution (designated as Paratungstate A) it may be concluded that the heptatungstate ion is the predominant species in such a solution. The anion structure of the previously described tributylammonium(5:24):tungstate [(C4H9)3NH]5H3W12O40 was elucidated by X-ray methods. Here the tungsten atoms show the same arrangement as in the α-dodecatungstatophosphate ion (Keggin structure).