Materials Data on NaAsSe2 by Materials Project

Abstract

NaAsSe2 crystallizes in the monoclinic Pc space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 11–15°. There are a spread of Na–Se bond distances ranging from 3.03–3.28 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–18°. There are a spread of Na–Se bond distances ranging from 2.98–3.09 Å. In the third Na1+ site, Na1+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are a spread of Na–Se bond distances ranging from 2.96–3.06 Å. In the fourth Na1+ site, Na1+ is bonded to six Se2- atoms to form a mixture of corner and edge-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are a spread of Na–Se bond distances ranging from 3.03–3.29 Å. There are four inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a distorted see-saw-like geometry to four Se2- atoms. There are a spread of As–Se bond distances ranging from 2.37–3.02 Å. In the second As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three Se2- atoms. There are a spread of As–Se bond distances ranging from 2.37–2.54 Å. In the third As3+ site, As3+ is bonded in a distorted see-saw-like geometry to four Se2- atoms. There are a spread of As–Se bond distances ranging from 2.37–2.98 Å. In the fourth As3+ site, As3+ is bonded in a distorted trigonal non-coplanar geometry to three Se2- atoms. There are a spread of As–Se bond distances ranging from 2.37–2.54 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Na1+ and two As3+ atoms to form SeNa3As2 square pyramids that share corners with five SeNa3As2 square pyramids, corners with three equivalent SeNa3As2 trigonal bipyramids, edges with three SeNa4As square pyramids, and an edgeedge with one SeNa3As2 trigonal bipyramid. In the second Se2- site, Se2- is bonded to three Na1+ and two As3+ atoms to form a mixture of distorted corner and edge-sharing SeNa3As2 trigonal bipyramids. In the third Se2- site, Se2- is bonded to four Na1+ and one As3+ atom to form SeNa4As square pyramids that share corners with five SeNa4As square pyramids, a cornercorner with one SeNa3As2 trigonal bipyramid, edges with five SeNa3As2 square pyramids, and an edgeedge with one SeNa3As2 trigonal bipyramid. In the fourth Se2- site, Se2- is bonded to three Na1+ and two As3+ atoms to form SeNa3As2 square pyramids that share corners with eight SeNa3As2 square pyramids and edges with four SeNa4As square pyramids. In the fifth Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to two equivalent Na1+ and two As3+ atoms. In the sixth Se2- site, Se2- is bonded to four Na1+ and one As3+ atom to form a mixture of corner and edge-sharing SeNa4As square pyramids. In the seventh Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to two equivalent Na1+ and two As3+ atoms. In the eighth Se2- site, Se2- is bonded to three Na1+ and two As3+ atoms to form distorted SeNa3As2 square pyramids that share corners with six SeNa4As square pyramids, corners with two equivalent SeNa3As2 trigonal bipyramids, and edges with four SeNa4As square pyramids.