Abstract

Concentration dependences of the lattice parameter a = f(x) and density ρ = f(x) have been studied for single crystals of the ternary solid solution Sr_0.8La_{0.2 – x}Lu_xF_2.2 (fluorite type, CaF₂; 0 ≤ x ≤ 0.2, x is the mole fraction of LuF₃) grown from the melt by the Bridgman method. The experimental dependences a(x) and ρ(x) obey the additivity law. Densitometric data support the scheme of heterovalent isomorphism in the Sr_0.8La_{0.2 – x}Lu_xF_2.2 solid solution: Sr²⁺ → (1 − 5x)La³⁺ + 5xLu³⁺ + \({\text{F}}_{{\text{i}}}^{ - }\). The excess of positive charge in the cationic sublattice of crystals is compensated by the formation of interstitial F_i^– ions. These regularities make it possible to calculate the lattice parameters and density of a large number of new functional fluoride materials—fluorite solid solutions \({{{\text{M}}}_{{1\,\, - \,\,x}}}{\text{R}}_{{(1\,\, - \,\,z)x}}^{'}{\text{R}}_{{zx}}^{{''}}{{{\text{F}}}_{{2\,\, + \,\,x}}}\) in ternary systems MF₂–R'F₃–R"F₃ (M = Ca, Sr, Ba; R', R" = La–Lu, Y).

中文翻译：

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三组分固溶体 Sr0.8La0.2 – xLuxF2.2 (0 ≤ x ≤ 0.2) 的晶格参数和单晶密度的浓度依赖性

摘要

的浓度依赖性的晶格参数一个= ˚F（X）和密度ρ= ˚F（X）已经研究了三元固溶体单晶的Sr _0.8的La _{0.2 - X}路_X ˚F _2.2（萤石型，的CaF ₂ ; 0≤ x ≤ 0.2，x是通过 Bridgman 方法从熔体中生长的 LuF ₃ )的摩尔分数。实验依赖a ( x ) 和 ρ( x) 服从可加律。光密度数据支持 Sr _0.8 La _{0.2 – x} Lu _x F _2.2固溶体中的异价同构方案： Sr ²⁺ → (1 − 5 x )La ³⁺ + 5 x Lu ³⁺ + \({\text{F }}_{{\text{i}}}^{ - }\)。晶体的阳离子亚晶格中过量的正电荷通过间隙 F _i ^-离子的形成得到补偿。这些规律使得计算大量新型功能氟化物材料——萤石固溶体的晶格参数和密度成为可能\({{{\text{M}}}_{{1\,\, - \,\,x}}}{\text{R}}_{{(1\,\, - \,\, z)x}}^{'}{\text{R}}_{{zx}}^{{''}}{{{\text{F}}}_{{2\,\, + \, \,x}}}\)在三元系统 MF ₂ –R'F ₃ –R"F ₃ (M = Ca, Sr, Ba; R', R" = La–Lu, Y)。