Materials Data on Ge5(Te4As)2 by Materials Project

Abstract

Ge5(AsTe4)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with four GeTe6 octahedra, edges with two equivalent AsTe6 octahedra, and edges with ten GeTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ge–Te bond distances ranging from 2.94–2.97 Å. In the second Ge4+ site, 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 two equivalent AsTe6 octahedra, and edges with nine GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (2.95 Å) and four longer (2.97 Å) Ge–Te bond lengths. In the third Ge4+ site, Ge4+ is bonded to six Te2- atoms to form GeTe6 octahedra that share corners with five GeTe6 octahedra, edges with four equivalent AsTe6 octahedra, and edges with six GeTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Ge–Te bond distances ranging from 2.90–2.99 Å. As2- is bonded to six Te2- atoms to form AsTe6 octahedra that share corners with three equivalent GeTe6 octahedra, corners with three equivalent AsTe6 octahedra, edges with two equivalent AsTe6 octahedra, and edges with seven GeTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of As–Te bond distances ranging from 2.94–2.97 Å. There are five inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to five Ge4+ and one As2- atom to form TeGe5As octahedra that share corners with three equivalent TeGe5As octahedra, corners with three equivalent TeGe2As3 square pyramids, edges with five TeGe5As octahedra, and edges with six TeGe4As square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. In the second Te2- site, Te2- is bonded to four Ge4+ and one As2- atom to form TeGe4As square pyramids that share a cornercorner with one TeGe6 octahedra, corners with five TeGe4As square pyramids, edges with six TeGe6 octahedra, and edges with two equivalent TeGe2As3 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the third Te2- site, Te2- is bonded in a square co-planar geometry to two equivalent Ge4+ and two equivalent As2- atoms. In the fourth Te2- site, Te2- is bonded to two Ge4+ and three equivalent As2- atoms to form TeGe2As3 square pyramids that share corners with three equivalent TeGe5As octahedra, corners with four TeGe4As square pyramids, edges with three TeGe5As octahedra, and edges with four TeGe4As square pyramids. The corner-sharing octahedral tilt angles are 0°. In the fifth Te2- site, Te2- is bonded to six Ge4+ atoms to form TeGe6 octahedra that share corners with two equivalent TeGe6 octahedra, corners with two equivalent TeGe4As square pyramids, edges with six equivalent TeGe5As octahedra, and edges with six TeGe4As square pyramids. The corner-sharing octahedral tilt angles are 0°.