Narducci Amy A., Ibers James A.
Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113.
Inorg Chem. 1998 Jul 27;37(15):3798-3801. doi: 10.1021/ic971594i.
Single crystals of CuTh(2)Te(6) form by a stoichiometric reaction of the elements at 1000 degrees C. The compound crystallizes in the space group -P2(1)/m with unit cell parameters a = 6.170(2) Å, b = 4.332(1) Å, c = 10.424(3) Å, beta = 98.85(1) degrees, and Z = 1 at 113 K. The structure was solved from single-crystal X-ray data. It consists of layers of [Th(2)Te(6)(-)] double chains joined by Cu(+) cations. Each Th atom is coordinated to eight Te atoms in a bicapped trigonal prismatic arrangement. There are three crystallographically unique Te atoms. Each ThTe(8) unit is bridged through one distinct Te atom, such that the capping Te atom of one unit forms the vertex of its neighbor. The two nonbridging Te atoms form infinite Te-Te chains along the exterior of the [Th(2)Te(6)(-)] layer. Copper atoms are coordinated to these Te atoms in a tetrahedral arrangement. Owing to the existence of Te-Te bonds of intermediate length, the assignment of formal oxidation states in this compound is not possible. Four-probe dc electrical conductivity measurements of a single crystal of CuTh(2)Te(6) indicate the compound is a semiconductor along [010]. Magnetic susceptibility measurements in the range 2-300 K show CuTh(2)Te(6) to be paramagnetic with &mgr;(eff) = 2.06 &mgr;(B) at 300 K. Single crystals of SrTh(2)Se(5) form from the reaction SrSe + Th + 3Sn + 3Se at 1000 degrees C. EDAX experiments show no tin present in several crystals analyzed. Transparent red blocks of SrTh(2)Se(5) crystallize in the space group -P2(1)/c with unit cell parameters a = 8.704(2) Å, b = 7.861(2) Å, c = 12.458(4) Å, beta = 90.00(2) degrees, and Z = 4 at 113 K. The structure, which is related to that of U(3)S(5), is a three-dimensional framework with Sr cations located in one-dimensional channels. There are two distinct Th environments, bicapped trigonal prismatic and distorted monocapped octahedral. There are no Se-Se bonds and so formal oxidation states of Sr(2+), Th(4+), and Se(2)(-) may be assigned.
CuTh₂Te₆的单晶通过元素在1000℃下的化学计量反应形成。该化合物在空间群-P2₁/m中结晶，在113K时的晶胞参数为a = 6.170(2) Å、b = 4.332(1) Å、c = 10.424(3) Å、β = 98.85(1)°，Z = 1。其结构由单晶X射线数据解析得出。它由通过Cu⁺阳离子连接的[Th₂Te₆⁻]双链层组成。每个Th原子以双帽三角棱柱排列与八个Te原子配位。有三个晶体学上独特的Te原子。每个ThTe₈单元通过一个独特的Te原子桥连，使得一个单元的帽状Te原子形成其相邻单元的顶点。两个非桥连的Te原子沿着[Th₂Te₆⁻]层的外部形成无限的Te-Te链。铜原子以四面体排列与这些Te原子配位。由于存在中等长度的Te-Te键，该化合物中形式氧化态的指定是不可能的。对CuTh₂Te₆单晶进行的四探针直流电导率测量表明，该化合物沿[010]方向是半导体。在2 - 300K范围内的磁化率测量表明，CuTh₂Te₆在300K时是顺磁性的，有效磁矩μ(eff) = 2.06 μ(B)。SrTh₂Se₅的单晶由SrSe + Th + 3Sn + 3Se在1000℃下的反应形成。能量散射X射线光谱（EDAX）实验表明，在分析的几块晶体中没有锡存在。SrTh₂Se₅的透明红色块状晶体在空间群-P2₁/c中结晶，在113K时的晶胞参数为a = 8.704(2) Å、b = 7.861(2) Å、c = 12.458(4) Å、β = 90.00(2)°，Z = 4。其结构与U₃S₅的结构相关，是一个三维框架，其中Sr阳离子位于一维通道中。有两种不同的Th环境，双帽三角棱柱和扭曲的单帽八面体。不存在Se-Se键，因此可以指定Sr²⁺、Th⁴⁺和Se²⁻的形式氧化态。
