Stetskiv Andrij, Tarasiuk Ivan, Misztal Renata, Pavlyuk Volodymyr
Ivano-Frankivsk National Medical University, Department of Chemistry, Galytska str. 2, 76018 Ivano-Frankivsk, Ukraine.
Department of Inorganic Chemistry, Ivan Franko Lviv National University, Kyryla and Mefodiya str. 6, 79005 Lviv, Ukraine.
Acta Crystallogr Sect E Struct Rep Online. 2013 Oct 12;69(Pt 11):i76. doi: 10.1107/S1600536813027335.
The quaternary thulium nickel/lithium distannide, TmNi1-x Li x Sn2 (x = 0.035), crystallizes in the ortho-rhom-bic LuNiSn2 structure type. The asymmetric unit contains three Tm sites, six Sn sites, two Ni sites and one Ni/Li site [relative occupancies = 0.895 (8):0.185 (8)]. Site symmetries are .m. for all atoms. The 17-, 18- and 19-vertex distorted pseudo-Frank-Kasper polyhedra are typical for all Tm atoms. Four Sn atoms are enclosed in a 12-vertex deformed cubo-octa-hedron, and another Sn atom is enclosed in a penta-gonal prism with three added atoms. A tricapped trigonal prism is typical for a further Sn atom. The coordination number for all Ni atoms and Ni/Li statistical mixtures is 12 (fourcapped trigonal prism [Ni/LiTm5Sn5]). Tm atoms form the base of a prism and Ni/Li atoms are at the centres of the side faces of an [SnTm6Ni/Li3] prism. These isolated prisms are implemented into three-dimensional-nets built out of Sn atoms. Electronic structure calculations using TB-LMTO-ASA suggest that the Tm and Ni/Li atoms form positively charged n[TmNi/Li] (m+) polycations which compensate the negative charge of 2n[Sn] (m-) polyanions. Analysis of the inter-atomic distances and electronic structure calculations indicate the dominance of a metallic type of bonding.
四元铥镍/锂二锡化物TmNi1-xLixSn2（x = 0.035）以正交晶系的LuNiSn2结构类型结晶。不对称单元包含三个Tm位点、六个Sn位点、两个Ni位点和一个Ni/Li位点[相对占有率 = 0.895 (8):0.185 (8)]。所有原子的位点对称性均为.m.。对于所有Tm原子，17、18和19顶点的扭曲伪弗兰克-卡斯珀多面体是典型的。四个Sn原子被包围在一个12顶点的变形立方八面体中，另一个Sn原子被包围在一个添加了三个原子的五角棱柱中。另一个Sn原子的典型结构是一个三帽三棱柱。所有Ni原子和Ni/Li统计混合物的配位数为12（四帽三棱柱[Ni/LiTm5Sn5]）。Tm原子构成棱柱的底面，Ni/Li原子位于[SnTm6Ni/Li3]棱柱侧面的中心。这些孤立的棱柱被整合到由Sn原子构成的三维网络中。使用TB-LMTO-ASA进行的电子结构计算表明，Tm和Ni/Li原子形成带正电的n[TmNi/Li] (m+)多阳离子，以补偿2n[Sn] (m-)多阴离子的负电荷。对原子间距离的分析和电子结构计算表明金属键占主导地位。
