Yin Wenlong, Lin Zuohong, Kang Lei, Kang Bin, Deng Jianguo, Lin Zheshuai, Yao Jiyong, Wu Yicheng
Institute of Chemical Materials, China Academy of Engineering Physics, P.O. Box 919-306, Mianyang, 621900, China.
Dalton Trans. 2015 Feb 7;44(5):2259-66. doi: 10.1039/c4dt02244k.
Two new quaternary selenides, namely Ba4Ga4SnSe12 and Ba6Ga2SnSe11, have been synthesized for the first time, representing the first two members in the A/M/Sn/Q (A = alkaline-earth metal; M = Al, Ga, In; Q = S, Se, Te) system. Ba4Ga4SnSe12 crystallizes in the non-centrosymmetric space group P4[combining macron]21/c of the tetragonal system and has a three-dimensional structure. Its three-dimensional framework is built up from corner-sharing GaSe4 and SnSe4 tetrahedra with eight-coordinated Ba(2+) cations residing in the cavities. Ba6Ga2SnSe11 crystallizes in a new structure type in the monoclinic centrosymmetric space group P21/c. The structure of Ba6Ga2SnSe11 features a zero-dimensional structure containing totally isolated distorted SnSe4 tetrahedra and a discrete Ga2Se7 unit with Ba(2+) cations located between them. On the basis of the diffuse-reflectance spectra, the band gaps are 2.16 (2) eV and 1.99 (2) eV for Ba4Ga4SnSe12 and Ba6Ga2SnSe11 respectively. In addition, the electronic structure calculation of Ba4Ga4SnSe12 indicates that it is a direct-gap semiconductor with the band gap mainly determined by the Ga4SnSe12 anionic framework.
首次合成了两种新型的四元硒化物，即Ba4Ga4SnSe12和Ba6Ga2SnSe11，它们是A/M/Sn/Q（A = 碱土金属；M = Al、Ga、In；Q = S、Se、Te）体系中的前两个成员。Ba4Ga4SnSe12属于四方晶系的非中心对称空间群P4[上加横线]21/c，具有三维结构。其三维骨架由共角顶的GaSe4和SnSe4四面体构成，八配位的Ba(2+)阳离子位于空穴中。Ba6Ga2SnSe11结晶于单斜中心对称空间群P21/c的一种新结构类型。Ba6Ga2SnSe结构的特征是零维结构，包含完全孤立的畸变SnSe4四面体和一个离散的Ga2Se7单元，Ba(2+)阳离子位于它们之间。基于漫反射光谱，Ba4Ga4SnSe12和Ba6Ga2SnSe11的带隙分别为2.16(2) eV和1.99(2) eV。此外，Ba4Ga4SnSe12的电子结构计算表明它是一种直接带隙半导体，其带隙主要由Ga4SnSe12阴离子骨架决定。
