Materials Data on Ge(SbTe2)2 by Materials Project

Abstract

Ge(SbTe2)2 is Calaverite-derived structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three Ge(SbTe2)2 sheets oriented in the (0, 0, 1) direction. Ge4+ is bonded to six equivalent Te2- atoms to form GeTe6 octahedra that share corners with six equivalent TeSb3Te3 octahedra, edges with six equivalent GeTe6 octahedra, and edges with six equivalent TeSb3Te3 octahedra. The corner-sharing octahedral tilt angles are 7°. All Ge–Te bond lengths are 3.01 Å. Sb2+ is bonded in a distorted T-shaped geometry to three equivalent Te2- atoms. All Sb–Te bond lengths are 3.03 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Sb2+ and three equivalent Te2- atoms to form TeSb3Te3 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent TeSb3Te3 octahedra. The corner-sharing octahedral tilt angles are 7°. All Te–Te bond lengths are 3.31 Å. In the second Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent Te2- atoms to form a mixture of distorted corner and edge-sharing TeGe3Te3 octahedra. The corner-sharing octahedral tilt angles are 0°.