Craig Andrew J, Stoyko Stanislav S, Bonnoni Allyson, Aitken Jennifer A
Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Ave, Pittsburgh PA 15282, USA.
Acta Crystallogr E Crystallogr Commun. 2020 Jun 19;76(Pt 7):1117-1121. doi: 10.1107/S2056989020007872. eCollection 2020 Jul 1.
The quaternary thio-germanates CuFeGeS (tetra-copper iron digermanium hepta-sulfide) and CuCoGeS (tetra-copper cobalt digermanium hepta-sulfide) were prepared in evacuated fused-silica ampoules high-temperature, solid-state synthesis using stoichiometric amounts of the elements at 1273 K. These isostructural compounds crystallize in the CuNiSiS structure type, which can be considered as a superstructure of cubic diamond or sphalerite. The monovalent (Cu), divalent (Fe or Co) and tetra-valent (Ge) cations adopt tetra-hedral geometries, each being surrounded by four S anions. The divalent cation and one of the sulfide ions lie on crystallographic twofold axes. These tetra-hedra share corners to create a three-dimensional framework structure. All of the tetra-hedra align along the same crystallographic direction, rendering the structure non-centrosymmetric and polar (space group 2). Analysis of X-ray powder diffraction data revealed that the structures are the major phase of the reaction products. Thermal analysis indicated relatively high melting temperatures, near 1273 K.
通过在1273K下使用化学计量比的元素进行高温固态合成，在抽真空的熔融石英安瓿中制备了四元硫代锗酸盐CuFeGeS（四铜铁二锗七硫化物）和CuCoGeS（四铜钴二锗七硫化物）。这些同构化合物以CuNiSiS结构类型结晶，该结构类型可被视为立方金刚石或闪锌矿的超结构。一价（Cu）、二价（Fe或Co）和四价（Ge）阳离子采用四面体几何构型，每个阳离子被四个S阴离子包围。二价阳离子和其中一个硫离子位于晶体学二重轴上。这些四面体共享角以形成三维骨架结构。所有四面体沿相同的晶体学方向排列，使结构具有非中心对称性和极性（空间群2）。X射线粉末衍射数据分析表明，这些结构是反应产物的主要相。热分析表明熔点相对较高，接近1273K。
