Materials Data on Ge(BiTe2)2 by Materials Project

Abstract

GeBi2Te4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three GeBi2Te4 sheets oriented in the (0, 0, 1) direction. Ge2+ is bonded to six equivalent Te2- atoms to form GeTe6 octahedra that share corners with six equivalent BiTe6 octahedra, edges with six equivalent GeTe6 octahedra, and edges with six equivalent BiTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. All Ge–Te bond lengths are 3.04 Å. Bi3+ is bonded to six Te2- atoms to form BiTe6 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent BiTe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three shorter (3.08 Å) and three longer (3.29 Å) Bi–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 6-coordinate geometry to three equivalent Bi3+ atoms. In the second Te2- site, Te2- is bonded to three equivalent Ge2+ and three equivalent Bi3+ atoms to form a mixture of edge and corner-sharing TeGe3Bi3 octahedra. The corner-sharing octahedral tilt angles are 0°.