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.