水热体系TeO2-K3PO4-H2O中一个新化合物——K2Te4O9·3H2O的合成与结晶

作者用水热法对TeO₂-K₃PO₄-H₂O体系作了初步的合成与结晶尝试。在给定的条件和组成范围内除了能形成TeO₂晶体外,还能生成一种点阵参数为a=b=10.734?,c=21.041?,α=β=90°,γ=120°的三方晶系的化合物γ,其分子式为K₂Te₄O₉·3H₂O。结晶区的产物主要取决于原料的k=TeO₂/K₃PO₄(克分子比:当k≤1.9时,仅生成γ晶体;k≥2.22时,单独生成TeO₂晶体;而当1.92晶体出现,本文还给出了γ晶相的DTA曲线和X射线粉末衍射谱线的相对强度与相应面间距的详细数据。 关键词：

SYNTHESIS AND CRYSTALLIZATION OF A NEW COMPOUND K2Te4O9·3H2O IN THE TeO2-K3PO4-H2O SYSTEM UNDER HYDROTHERMAL CONDITIONS

We investigated preliminarilly the synthesis and crystallization in the system TeO₂-K₃PO₄-H₂O under hydrothermal conditions. It was found that in addition to the crystals of TeO₂, crystals of a new phase which we called γ could be obtained in the given range of constituent and growth conditions. The γ crystal belongs to trigonal system with α= b=10.734 ?, c=21.041?, α=β=90°, γ=120°. The formula of γ is K₂Te₄O₉·3H₂O. Furthermore,it was shown that the crystallized product in the crystallization zone depends mainly on the molar ratio of starting materials k=TeO₂/K₃PO₄ in the system. When k≤1.90, the crystallized phase only consists of γ crystals, k≥2.22, only TeO₂ crystals appears, while 1.902 are present together.Finally, the DTA curve and the relative intensities and corresponding d-values of X-ray powder diffraction pattern of γ-phase are also given.
Keywords：