Materials Data on Na2GeSe3 by Materials Project

Abstract

Na2GeSe3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five Se2- atoms to form distorted NaSe5 trigonal bipyramids that share corners with six equivalent NaSe6 octahedra, corners with two equivalent GeSe4 tetrahedra, corners with two equivalent NaSe5 trigonal bipyramids, edges with two equivalent NaSe6 octahedra, edges with two equivalent GeSe4 tetrahedra, and edges with two equivalent NaSe5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 9–86°. There are a spread of Na–Se bond distances ranging from 3.01–3.26 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with three equivalent GeSe4 tetrahedra, corners with six equivalent NaSe5 trigonal bipyramids, edges with three equivalent NaSe6 octahedra, edges with two equivalent GeSe4 tetrahedra, and edges with two equivalent NaSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 23°. There are a spread of Na–Se bond distances ranging from 2.99–3.37 Å. Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share corners with three equivalent NaSe6 octahedra, corners with two equivalent GeSe4 tetrahedra, corners with two equivalent NaSe5 trigonal bipyramids, edges with two equivalent NaSe6 octahedra, and edges with two equivalent NaSe5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 26–69°. There are two shorter (2.35 Å) and two longer (2.43 Å) Ge–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to five Na1+ and one Ge4+ atom. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+ and two equivalent Ge4+ atoms. In the third Se2- site, Se2- is bonded to four Na1+ and one Ge4+ atom to form a mixture of distorted edge and corner-sharing SeNa4Ge trigonal bipyramids.