Abstract

Unit cell parameters a_cal(x) and X-ray densities ρ_X(x) are calculated in terms of a model that accounts for ionic bonding, additivity of properties, and dimensional factor upon aliovalent substitutions for 45 new nonstoichiometric phases Sm_{1 − x}R_xF_{2 + x}, Eu_{1 − x}R_xF_{2 + x} and Yb_{1 − x}R_xF_{2 + x} (R = La−Lu, Y) based on SmF₂, EuF₂, and YbF₂ fluorite matrices (the fluorite CaF₂ type). A comparison of the calculated unit cell parameters a_cal(x) and the experimental a(x) values available in the literature for these phases shows satisfactory match. Concentration-dependent relationships a_cal(x) and ρ_X(x) can be used for monitoring the composition of melt-grown Sm_{1 − x}R_xF_{2 + x}, Eu_{1 − x}R_xF_{2 + x}, and Yb_{1 − x}R_xF_{2 + x} crystals in studies of their defect structures and fundamental properties.

中文翻译：

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Sm1 – xRxF2 + x、Eu1 – xRxF2 + x 和 Yb1 – xRxF2 + x（R 是稀土元素）晶体的晶胞参数和密度计算

摘要

晶胞参数a _cal ( x ) 和 X 射线密度 ρ _X ( x ) 是根据一个模型计算的，该模型考虑了离子键合、性质的可加性和 45 个新的非化学计量相 Sm _{1 − x 的}异价取代时的尺寸因子[R _X ˚F _{2 + X}，铕_{1 - X} - [R _X ˚F _{2 + X}和Yb _{1 - X} - [R _X ˚F _{2 + X}（R =腊路，Y）的基础上SMF ₂，氟化铕₂，和为YbF ₂萤石基质（萤石 CaF ₂型）。计算的晶胞参数a _cal ( x ) 和文献中可用的实验a ( x ) 值的比较显示出令人满意的匹配。浓度依赖关系a _cal ( x ) 和 ρ _X ( x ) 可用于监测熔体生长的 Sm _{1 − x} R _x F _{2 + x}、Eu _{1 − x} R _x F _{2 + x}和 Yb 的组成_{1 - x} R _x F _{2 + x}晶体的缺陷结构和基本特性研究。