Materials Data on Ge2Bi2Te5 by Materials Project

Ge2Bi2Te5 is Caswellsilverite-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ge2Bi2Te5 sheet oriented in the (0, 0, 1) direction. Ge2+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent BiTe6 octahedra, edges with three equivalent BiTe6 octahedra, and edges with nine equivalent GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are three shorter (3.02 Å) and three longer (3.07 Å) Ge–Te bond lengths. 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 (3.07 Å) and three longer (3.29 Å) Bi–Te bond lengths. There are three 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 corner and edge-sharing TeGe3Bi3 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third Te2- site, Te2- is bonded to six equivalent Ge2+ atoms to form TeGe6 octahedra that share corners with six equivalent TeGe3Bi3 octahedra and edges with twelve TeGe6 octahedra. The corner-sharing octahedral tilt angles are 1°.