DOI: 10.17188/1278171
title: Materials Data on Na3CuSnSe4 by Materials Project

description: Na3CuSnSe4 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 six Se2- atoms to form NaSe6 octahedra that share corners with four equivalent NaSe5 square pyramids, corners with two equivalent CuSe4 tetrahedra, corners with two equivalent SnSe4 tetrahedra, corners with five equivalent NaSe5 trigonal bipyramids, edges with two equivalent NaSe6 octahedra, edges with two equivalent CuSe4 tetrahedra, edges with two equivalent SnSe4 tetrahedra, an edgeedge with one NaSe5 trigonal bipyramid, and a faceface with one NaSe5 square pyramid. There are a spread of Na–Se bond distances ranging from 3.00–3.32 Å. In the second Na1+ site, Na1+ is bonded to five Se2- atoms to form NaSe5 trigonal bipyramids that share corners with five equivalent NaSe6 octahedra, corners with two equivalent NaSe5 square pyramids, a cornercorner with one CuSe4 tetrahedra, corners with five equivalent SnSe4 tetrahedra, an edgeedge with one NaSe6 octahedra, edges with two equivalent NaSe5 square pyramids, edges with two equivalent CuSe4 tetrahedra, and an edgeedge with one NaSe5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 39–55°. There are a spread of Na–Se bond distances ranging from 2.96–3.17 Å. In the third Na1+ site, Na1+ is bonded to five Se2- atoms to form NaSe5 square pyramids that share corners with four equivalent NaSe6 octahedra, corners with three equivalent CuSe4 tetrahedra, corners with three equivalent SnSe4 tetrahedra, corners with two equivalent NaSe5 trigonal bipyramids, an edgeedge with one NaSe5 square pyramid, an edgeedge with one CuSe4 tetrahedra, an edgeedge with one SnSe4 tetrahedra, edges with two equivalent NaSe5 trigonal bipyramids, and a faceface with one NaSe6 octahedra. The corner-sharing octahedra tilt angles range from 34–67°. There are a spread of Na–Se bond distances ranging from 2.96–3.25 Å. Cu1+ is bonded to four Se2- atoms to form distorted CuSe4 tetrahedra that share corners with two equivalent NaSe6 octahedra, corners with three equivalent NaSe5 square pyramids, corners with two equivalent SnSe4 tetrahedra, a cornercorner with one NaSe5 trigonal bipyramid, edges with two equivalent NaSe6 octahedra, an edgeedge with one NaSe5 square pyramid, an edgeedge with one SnSe4 tetrahedra, and edges with two equivalent NaSe5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 17–57°. There are a spread of Cu–Se bond distances ranging from 2.42–2.66 Å. 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 equivalent CuSe4 tetrahedra, corners with five equivalent NaSe5 trigonal bipyramids, edges with two equivalent NaSe6 octahedra, an edgeedge with one NaSe5 square pyramid, and an edgeedge with one CuSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–64°. There are three shorter (2.57 Å) and one longer (2.58 Å) Sn–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to four Na1+, one Cu1+, and one Sn4+ atom. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to four Na1+, one Cu1+, and one Sn4+ atom. In the third Se2- site, Se2- is bonded to four Na1+, one Cu1+, and one Sn4+ atom to form a mixture of distorted edge and corner-sharing SeNa4CuSn pentagonal pyramids. In the fourth Se2- site, Se2- is bonded to four Na1+, one Cu1+, and one Sn4+ atom to form a mixture of distorted edge and corner-sharing SeNa4CuSn pentagonal pyramids.