Materials Data on Na2Ge2Se5 by Materials Project

Abstract

Na2Ge2Se5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Na–Se bond distances ranging from 3.13–3.55 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Na–Se bond distances ranging from 3.06–3.56 Å. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four Se2- atoms to form corner-sharing GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.32–2.42 Å. In the second Ge4+ site, Ge4+ is bonded to four Se2- atoms to form corner-sharing GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.33–2.41 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Na1+ and one Ge4+ atom to form distorted SeNa3Ge trigonal pyramids that share corners with six equivalent SeNa4Ge square pyramids and corners with two equivalent SeNa3Ge trigonal pyramids. In the second Se2- site, Se2- is bonded to four Na1+ and one Ge4+ atom to form distorted SeNa4Ge square pyramids that share corners with six equivalent SeNa3Ge trigonal pyramids and edges with two equivalent SeNa4Ge square pyramids. In the third Se2- site, Se2- is bonded in a water-like geometry to two equivalent Ge4+ atoms. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Na1+ and two Ge4+ atoms. In the fifth Se2- site, Se2- is bonded in a distorted square co-planar geometry to two equivalent Na1+ and two equivalent Ge4+ atoms.