Abstract

The polymorphic transformations in K_0.945Ag_0.055NO₃ are studied by optical spectroscopy and X-ray diffraction. It is established that one structural transformation occurs in this crystal in the temperature range from room temperature to the melting point. The growth of new crystal modification growth is accompanied by the formation and growth of daughter modification nuclei inside the matrix crystal. The equilibrium temperature between modifications II and III (Т₀ = 393 ± 1 K) and the unit-cell parameters for crystals of these modifications are determined. At room temperature, the orthorhombic modification parameters are a = 5.407 Å, b = 9.156 Å, and c = 6.410 Å; sp. gr. Pnma. The parameters of high-temperature rhombohedral modification are a = 5.405 Å and c = 9.712 Å; sp. gr. \(R{\bar {3}}m\). It is established using X-ray diffraction analysis that the II → III polymorphic transformation in K_0.945Ag_0.055NO₃ is of the single crystal–single crystal type.

中文翻译：

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K 0.945 Ag 0.055 NO 3单晶中的多态转变

摘要

通过光谱学和X射线衍射研究了K _0.945 Ag _0.055 NO ₃中的多晶型转变。已经确定在从室温到熔点的温度范围内在该晶体中发生一种结构转变。新晶体修饰生长的生长伴随着基质晶体内部子修饰核的形成和生长。修改II和III之间的平衡温度（Т ₀对于这些修饰的晶体晶胞参数= 393±1 K）和被确定。在室温下，斜方晶系修饰参数为a = 5.407Å，b = 9.156Å和c= 6.410Å; sp。gr。Pnma。高温菱形体修饰的参数为a = 5.405Å和c = 9.712Å；sp。gr。\（R {\ bar {3}} m \）。通过X射线衍射分析_可以确定，K _0.945 Ag _0.055 NO ₃中的II→III多晶型转变是单晶-单晶类型。