Intricate Li–Sn Disorder in Rare-Earth Metal–Lithium Stannides. Crystal Chemistry of RE 3 Li 4–x Sn 4+x (RE = La–Nd, Sm; x 7 Li 8–x Sn 10+x ( x ≈ 2.0)
Intricate Li–Sn Disorder in Rare-Earth Metal–Lithium Stannides. Crystal Chemistry of RE 3 Li 4–x Sn 4+x (RE = La–Nd, Sm; x 7 Li 8–x Sn 10+x ( x ≈ 2.0)
复制标题
稀土金属-锡化锂中复杂的锂-锡无序。
DOI：
10.1021/acs.inorgchem.8b00583
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发表时间：
2018
影响因子：
4.6
通讯作者：
Bobev, Svilen
中科院分区：
文献类型：
--
作者：
Suen, Nian-Tzu;Guo, Sheng-Ping;Hoos, James;Bobev, Svilen
报道了通式为 RE3Li4–xSn4+x(RE = La–Nd, Sm) 和 Eu7Li8–xSn10+x 的六种稀土金属-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。它们的晶体结构是使用单晶 X 射线衍射方法确定的。 RE3Li4–xSn4+x相在斜方体心心空间群Immm(No.71)中结晶，结构类型为Zr3Cu4Si4(Pearson codeoI22)，Eu7Li8–xSn10+x相在斜方基心空间群Cmmm(No.65)中结晶，结构类型为Ce7Li8Ge10 （皮尔逊代码 C50）。这两种结构都可以被认为是[RESn2]n[RELi2Sn]同系物的一部分，其中结构是假想的RESn2（类AlB2结构类型）和RELi2Sn（类MgAl2Cu结构类型）片段的共生。仔细检查结构表明存在复杂的占据性Li-Sn无序，显然是由结构驱动来实现最佳价电子数的。这一基于实验结果的结论得到了使用紧束缚线性松饼罐轨道方法进行的详细电子结构计算的支持。
Reported are the syntheses, crystal structures, and electronic structures of six rare-earth metal–lithium stannides with the general formulas RE3Li4–xSn4+x(RE = La–Nd, Sm) and Eu7Li8–xSn10+x. 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 RE3Li4–xSn4+xphases crystallize in the orthorhombic body-centered space groupImmm(No. 71) with the Zr3Cu4Si4structure type (Pearson codeoI22), and the Eu7Li8–xSn10+xphase crystallizes in the orthorhombic base-centered space groupCmmm(No. 65) with the Ce7Li8Ge10structure type (Pearson codeoC50). Both structures can be consdered as part of the [RESn2]n[RELi2Sn]mhomologous series, wherein the structures are intergrowths of imaginary RESn2(AlB2-like structure type) and RELi2Sn (MgAl2Cu-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.