DOI: 10.17188/1276276
title: Materials Data on Na2SnSe3 by Materials Project

description: Na2SnSe3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a distorted pentagonal planar geometry to five Se2- atoms. There are a spread of Na–Se bond distances ranging from 2.90–3.31 Å. In the second Na1+ site, Na1+ is bonded to five Se2- atoms to form distorted NaSe5 square pyramids that share a cornercorner with one NaSe6 octahedra, corners with four SnSe4 tetrahedra, corners with two NaSe5 trigonal bipyramids, an edgeedge with one NaSe5 square pyramid, an edgeedge with one SnSe4 tetrahedra, and an edgeedge with one NaSe5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 47°. There are a spread of Na–Se bond distances ranging from 2.86–3.27 Å. In the third 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 2.86–3.67 Å. In the fourth Na1+ site, Na1+ is bonded to five Se2- atoms to form NaSe5 trigonal bipyramids that share a cornercorner with one NaSe6 octahedra, a cornercorner with one NaSe5 square pyramid, corners with six SnSe4 tetrahedra, a cornercorner with one NaSe5 trigonal bipyramid, an edgeedge with one NaSe6 octahedra, an edgeedge with one NaSe5 square pyramid, and edges with two NaSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 59°. There are a spread of Na–Se bond distances ranging from 2.97–3.04 Å. In the fifth Na1+ site, Na1+ is bonded to six Se2- atoms to form distorted NaSe6 octahedra that share a cornercorner with one NaSe5 square pyramid, corners with five SnSe4 tetrahedra, corners with two NaSe5 trigonal bipyramids, an edgeedge with one SnSe4 tetrahedra, edges with two NaSe5 trigonal bipyramids, and a faceface with one NaSe6 octahedra. There are a spread of Na–Se bond distances ranging from 2.93–3.41 Å. In the sixth Na1+ site, Na1+ is bonded to five Se2- atoms to form distorted NaSe5 trigonal bipyramids that share a cornercorner with one NaSe6 octahedra, a cornercorner with one NaSe5 square pyramid, corners with six SnSe4 tetrahedra, a cornercorner with one NaSe5 trigonal bipyramid, an edgeedge with one NaSe6 octahedra, and edges with two NaSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 48°. There are a spread of Na–Se bond distances ranging from 2.89–3.11 Å. There are four inequivalent Sn4+ sites. In the first Sn4+ site, Sn4+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share a cornercorner with one NaSe6 octahedra, a cornercorner with one NaSe5 square pyramid, corners with two SnSe4 tetrahedra, corners with five NaSe5 trigonal bipyramids, and an edgeedge with one NaSe5 square pyramid. The corner-sharing octahedral tilt angles are 46°. There are a spread of Sn–Se bond distances ranging from 2.51–2.66 Å. In the second Sn4+ site, Sn4+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with two equivalent NaSe6 octahedra, corners with three equivalent NaSe5 square pyramids, corners with two SnSe4 tetrahedra, and corners with four NaSe5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 74–78°. There are a spread of Sn–Se bond distances ranging from 2.52–2.64 Å. In the third Sn4+ site, Sn4+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with two equivalent NaSe6 octahedra, corners with two equivalent SnSe4 tetrahedra, and corners with four equivalent NaSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. There are a spread of Sn–Se bond distances ranging from 2.51–2.64 Å. In the fourth Sn4+ site, Sn4+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with two equivalent NaSe6 octahedra, corners with two equivalent SnSe4 tetrahedra, corners with two equivalent NaSe5 trigonal bipyramids, and edges with two equivalent NaSe6 octahedra. The corner-sharing octahedral tilt angles are 61°. There are a spread of Sn–Se bond distances ranging from 2.51–2.65 Å. There are eleven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Na1+ and two Sn4+ atoms to form distorted SeNa3Sn2 trigonal bipyramids that share a cornercorner with one SeNa4Sn square pyramid, corners with two SeNa3Sn2 trigonal bipyramids, a cornercorner with one SeNa2Sn2 trigonal pyramid, and edges with three SeNa4Sn trigonal bipyramids. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the fourth Se2- site, Se2- is bonded to four Na1+ and one Sn4+ atom to form distorted SeNa4Sn trigonal bipyramids that share a cornercorner with one SeNa4Sn square pyramid, a cornercorner with one SeNa4Sn trigonal bipyramid, a cornercorner with one SeNa2Sn2 trigonal pyramid, an edgeedge with one SeNa3Sn2 trigonal bipyramid, and an edgeedge with one SeNa2Sn2 trigonal pyramid. In the fifth Se2- site, Se2- is bonded to four Na1+ and one Sn4+ atom to form a mixture of distorted corner and edge-sharing SeNa4Sn trigonal bipyramids. In the sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the seventh Se2- site, Se2- is bonded to two Na1+ and two Sn4+ atoms to form distorted SeNa2Sn2 trigonal pyramids that share corners with two SeNa3Sn2 trigonal bipyramids and an edgeedge with one SeNa4Sn trigonal bipyramid. In the eighth Se2- site, Se2- is bonded to four Na1+ and one Sn4+ atom to form distorted SeNa4Sn trigonal bipyramids that share a cornercorner with one SeNa4Sn trigonal bipyramid, an edgeedge with one SeNa4Sn square pyramid, and edges with three SeNa3Sn2 trigonal bipyramids. In the ninth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Na1+ and one Sn4+ atom. In the tenth Se2- site, Se2- is bonded to four Na1+ and one Sn4+ atom to form distorted SeNa4Sn square pyramids that share corners with four SeNa3Sn2 trigonal bipyramids and an edgeedge with one SeNa4Sn trigonal bipyramid. In the eleventh Se2- site, Se2- is bonded in a 4-coordinate geometry to three Na1+ and two Sn4+ atoms.