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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Na6Ge2Se7 by Materials Project

Na6Ge2Se7 crystallizes in the monoclinic C2/c 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 NaSe6 octahedra that share corners with two equivalent NaSe6 octahedra, corners with two equivalent GeSe4 tetrahedra, edges with four equivalent NaSe6 octahedra, and edges with two equivalent GeSe4 tetrahedra. The corner-sharing octahedral tilt angles are 5°. There are a spread of Na–Se bond distances ranging from 2.91–3.24 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share corners with two NaSe6 octahedra, a cornercorner with one GeSe4 tetrahedra, edges with four NaSe6 octahedra, and edges with three equivalent GeSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 5–40°. There are a spread of Na–Se bond distances ranging from 3.02–3.53 Å. In the third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four Se2- atoms. There are two shorter (2.87 Å) and two longer (2.94 Å) Na–Se bond lengths. In the fourth 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 2.99–3.60 Å. Ge4+ is bonded to four Se2- atoms to form GeSe4 tetrahedra that share corners with two NaSe6 octahedra, a cornercorner with one GeSe4 tetrahedra, and edges with four NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 20–59°. There are a spread of Ge–Se bond distances ranging from 2.36–2.44 Å. There are four 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 to five Na1+ and one Ge4+ atom to form a mixture of edge and corner-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the third Se2- site, Se2- is bonded to five Na1+ and one Ge4+ atom to form a mixture of distorted edge and corner-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 0–76°. In the fourth Se2- site, Se2- is bonded in a 2-coordinate geometry to four Na1+ and two equivalent Ge4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na3GeSe3 by Materials Project

Na3GeSe3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five Se2- atoms to form distorted NaSe5 square pyramids that share corners with eight NaSe6 octahedra, corners with four equivalent NaSe5 square pyramids, edges with three NaSe6 octahedra, and faces with two NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 12–53°. There are a spread of Na–Se bond distances ranging from 2.93–3.52 Å. In the second Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share corners with eight NaSe6 octahedra, corners with three equivalent NaSe5 square pyramids, edges with two equivalent NaSe6 octahedra, edges with two equivalent NaSe5 square pyramids, faces with two equivalent NaSe6 octahedra, and a faceface with one NaSe5 square pyramid. The corner-sharing octahedra tilt angles range from 36–77°. There are a spread of Na–Se bond distances ranging from 3.00–3.31 Å. In the third Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share corners with six equivalent NaSe6 octahedra, corners with five equivalent NaSe5 square pyramids, edges with three equivalent NaSe6 octahedra, an edgeedge with one NaSe5 square pyramid, faces with two equivalent NaSe6 octahedra, and a faceface with one NaSe5 square pyramid. The corner-sharing octahedra tilt angles range from 37–77°. There are a spread of Na–Se bond distances ranging from 3.00–3.38 Å. Ge3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are a spread of Ge–Se bond distances ranging from 2.38–2.40 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to five Na1+ and one Ge3+ atom. In the second Se2- site, Se2- is bonded in a 7-coordinate geometry to six Na1+ and one Ge3+ atom. In the third Se2- site, Se2- is bonded to six Na1+ and one Ge3+ atom to form distorted face-sharing SeNa6Ge pentagonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2GeSe3 by Materials Project

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.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na4Ge2Se5 by Materials Project

Na4Ge2Se5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five 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 5–13°. There are a spread of Na–Se bond distances ranging from 3.06–3.21 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 4–13°. There are a spread of Na–Se bond distances ranging from 3.00–3.27 Å. In the third 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 3–9°. There are a spread of Na–Se bond distances ranging from 3.04–3.21 Å. In the fourth 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 3–4°. There are four shorter (3.12 Å) and two longer (3.16 Å) Na–Se bond lengths. In the fifth 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 3–8°. There are a spread of Na–Se bond distances ranging from 2.96–3.26 Å. There are two inequivalent Ge3+ sites. In the first Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are two shorter (2.36 Å) and one longer (2.49 Å) Ge–Se bond lengths. In the second Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are two shorter (2.36 Å) and one longer (2.48 Å) Ge–Se bond lengths. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to five Na1+ and one Ge3+ atom to form a mixture of edge and corner-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 0–89°. In the second Se2- site, Se2- is bonded to four Na1+ and two Ge3+ atoms to form a mixture of distorted edge and corner-sharing SeNa4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 0–86°. In the third Se2- site, Se2- is bonded to five Na1+ and one Ge3+ atom to form a mixture of edge and corner-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 0–89°. In the fourth Se2- site, Se2- is bonded to five Na1+ and one Ge3+ atom to form a mixture of edge and corner-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 0–87°. In the fifth Se2- site, Se2- is bonded to five Na1+ and one Ge3+ atom to form a mixture of distorted edge and corner-sharing SeNa5Ge octahedra. The corner-sharing octahedra tilt angles range from 0–87°.

36 MATERIALS SCIENCE↗