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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaAsSe2 by Materials Project

NaAsSe2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 14–21°. There are a spread of Na–Se bond distances ranging from 2.98–3.18 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 15–21°. There are a spread of Na–Se bond distances ranging from 2.98–3.20 Å. There are two inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of As–Se bond distances ranging from 2.35–2.51 Å. In the second As3+ site, As3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of As–Se bond distances ranging from 2.35–2.51 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a see-saw-like geometry to two Na1+ and two equivalent As3+ atoms. In the second Se2- site, Se2- is bonded to four equivalent Na1+ and one As3+ atom to form a mixture of edge and corner-sharing SeNa4As square pyramids. In the third Se2- site, Se2- is bonded to four equivalent Na1+ and one As3+ atom to form a mixture of edge and corner-sharing SeNa4As square pyramids. In the fourth Se2- site, Se2- is bonded in a see-saw-like geometry to two Na1+ and two equivalent As3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaAsSe2 by Materials Project

NaAsSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with two equivalent AsSe6 octahedra, corners with four equivalent NaSe6 octahedra, edges with four equivalent NaSe6 octahedra, and edges with eight equivalent AsSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are four shorter (2.81 Å) and two longer (3.17 Å) Na–Se bond lengths. As3+ is bonded to six equivalent Se2- atoms to form AsSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with four equivalent AsSe6 octahedra, edges with four equivalent AsSe6 octahedra, and edges with eight equivalent NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are two shorter (2.71 Å) and four longer (2.81 Å) As–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent As3+ atoms to form a mixture of edge and corner-sharing SeNa3As3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the second Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent As3+ atoms to form a mixture of edge and corner-sharing SeNa3As3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are one shorter (2.71 Å) and two longer (2.81 Å) Se–As bond lengths. In the third Se2- site, Se2- is bonded to three equivalent Na1+ and three equivalent As3+ atoms to form a mixture of edge and corner-sharing SeNa3As3 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are one shorter (2.71 Å) and two longer (2.81 Å) Se–As bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaAsSe2 by Materials Project

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.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na3AsSe3 by Materials Project

Na3AsSe3 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six equivalent Se2- atoms to form a mixture of distorted edge, corner, and face-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 26–46°. There are three shorter (2.99 Å) and three longer (3.17 Å) Na–Se bond lengths. In the second Na1+ site, Na1+ is bonded to six equivalent Se2- atoms to form a mixture of distorted edge, corner, and face-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 26–44°. There are three shorter (3.00 Å) and three longer (3.18 Å) Na–Se bond lengths. In the third Na1+ site, Na1+ is bonded to six equivalent Se2- atoms to form a mixture of edge, corner, and face-sharing NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 35–59°. There are three shorter (3.11 Å) and three longer (3.33 Å) Na–Se bond lengths. As3+ is bonded in a trigonal non-coplanar geometry to three equivalent Se2- atoms. All As–Se bond lengths are 2.44 Å. Se2- is bonded to six Na1+ and one As3+ atom to form a mixture of distorted edge, corner, and face-sharing SeNa6As pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaAsSe2 by Materials Project

NaAsSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Na1+ is bonded to six Se2- atoms to form NaSe6 octahedra that share corners with six equivalent NaSe6 octahedra, edges with four equivalent NaSe6 octahedra, and edges with eight equivalent AsSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.78 Å) and four longer (2.83 Å) Na–Se bond lengths. As3+ is bonded to six Se2- atoms to form AsSe6 octahedra that share corners with six equivalent AsSe6 octahedra, edges with four equivalent AsSe6 octahedra, and edges with eight equivalent NaSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.78 Å) and four longer (2.83 Å) As–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Na1+ and four equivalent As3+ atoms to form a mixture of corner and edge-sharing SeNa2As4 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second Se2- site, Se2- is bonded to four equivalent Na1+ and two equivalent As3+ atoms to form SeNa4As2 octahedra that share corners with six equivalent SeNa4As2 octahedra and edges with twelve SeNa2As4 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗