Materials Data on Ge2Te5As2 by Materials Project

Abstract

As2Ge2Te5 is MAX Phase-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one As2Ge2Te5 sheet oriented in the (0, 0, 1) direction. Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent AsTe6 octahedra, edges with three equivalent AsTe6 octahedra, and edges with nine equivalent GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are three shorter (2.97 Å) and three longer (3.00 Å) Ge–Te bond lengths. As1+ is bonded to six Te2- atoms to form AsTe6 octahedra that share corners with three equivalent GeTe6 octahedra, edges with three equivalent GeTe6 octahedra, and edges with six equivalent AsTe6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (2.86 Å) and three longer (3.04 Å) As–Te bond lengths. There are three inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to three equivalent Ge4+ and three equivalent As1+ atoms to form TeGe3As3 octahedra that share corners with three equivalent TeGe6 octahedra and edges with nine TeGe3As3 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent As1+ atoms. In the third Te2- site, Te2- is bonded to six equivalent Ge4+ atoms to form a mixture of edge and corner-sharing TeGe6 octahedra. The corner-sharing octahedral tilt angles are 1°.