Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.
College of Chemistry and Chemical Engineering , Yangzhou University , Yangzhou 225002 , P. R. China.
Inorg Chem. 2018 May 7;57(9):5632-5641. doi: 10.1021/acs.inorgchem.8b00583. Epub 2018 Apr 20.
Reported are the syntheses, crystal structures, and electronic structures of six rare-earth metal-lithium stannides with the general formulas RELiSn (RE = La-Nd, Sm) and EuLiSn. These new ternary compounds have been synthesized by high-temperature reactions of the corresponding elements. Their crystal structures have been established using single-crystal X-ray diffraction methods. The RELiSn phases crystallize in the orthorhombic body-centered space group Immm (No. 71) with the ZrCuSi structure type (Pearson code oI22), and the EuLiSn phase crystallizes in the orthorhombic base-centered space group Cmmm (No. 65) with the CeLiGe structure type (Pearson code oC50). Both structures can be consdered as part of the [RESn] [RELiSn] homologous series, wherein the structures are intergrowths of imaginary RESn (AlB-like structure type) and RELiSn (MgAlCu-like structure type) fragments. Close examination the structures indicates complex occupational Li-Sn disorder, apparently governed by the drive of the structure to achieve an optimal number of valence electrons. This conclusion based on experimental results is supported by detailed electronic structure calculations, carried out using the tight-binding linear muffin-tin orbital method.
报告了六种具有通式 RELiSn（RE=La-Nd、Sm）和 EuLiSn 的稀土金属-锂锡化物的合成、晶体结构和电子结构。这些新的三元化合物是通过相应元素的高温反应合成的。它们的晶体结构是通过单晶 X 射线衍射方法确定的。RELiSn 相在正交体心空间群 Immm（No.71）中结晶，具有 ZrCuSi 结构类型（Pearson 码 oI22），EuLiSn 相在正交底心空间群 Cmmm（No.65）中结晶，具有 CeLiGe 结构类型（Pearson 码 oC50）。这两种结构都可以被认为是 [RESn] [RELiSn] 同系物的一部分，其中结构是假想的 RESn（AlB 结构类型）和 RELiSn（MgAlCu 结构类型）片段的相互生长。仔细观察结构表明存在复杂的 Li-Sn 占位无序，显然是由结构实现最佳价电子数的驱动所致。这一基于实验结果的结论得到了详细电子结构计算的支持，该计算是使用紧束缚线性 muffin-tin 轨道方法进行的。
