具有K_2NiF_4型结构的复合氧化物Sm_(2-x)Sr_xNiO_4的合成和结构测定

Synthesis and Crystal Structure of Rare Earth Complex Oxides Sm_(2-x)Sr_x NiO_4 with K_2NiF_4 Type

本文报导了Sm_(2-x)Sr_xNiO_4系列稀土复合氧化物的形成范围及其结晶化学特征。XRD分析表明,在0.4≤x≤1.2范围内,能形成K_2NiF_4型结构的稀土复合氧化物,随Sr掺入量x的增加,其结构由空间群为D_(2A)^(23)-Fmmm的正交晶系逐渐向空间群为D_(4h)^(17)I_4/mmm的四方晶系过渡。本文从容纳因子t值、Ni离子的变价(Ni^(2+)/Ni^(3+))和NiO_6八面体的畸变角度探讨了Sr^(2+)的掺入量对结构的影响。

The rare earth complex Oxides Sm2-xSrxNiO4 were prepared by Sol-Gel method and characterized by powder XRD. The results showed that Sm2-xSrxNiO4 possessed K2NiF4 type structure within the range of 0.4≤x≤1.2. The space group transfered from orthorhombic D2k23-Fmmm to tetragonal D4k17-I4/mmm with increasing content of Sr2+ in the structure. The effect of Sr2+ substitution oh the structure was discussed in terms of tolerent facter (t), variable valence character of Ni ion (Mit+/ Ni3+) and distortion of NiO6 octahedra.