Materials Data on K2SnSe3 by Materials Project
K2SnSe3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six Se2- atoms to form KSe6 octahedra that share corners with two equivalent KSe6 octahedra, corners with three equivalent SnSe4 tetrahedra, edges with three equivalent KSe6 octahedra, and edges with two equivalent SnSe4 tetrahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of K–Se bond distances ranging from 3.41–3.58 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of K–Se bond distances ranging from 3.44–3.66 Å. Sn4+ is bonded to four Se2- atoms to form SnSe4 tetrahedra that share corners with three equivalent KSe6 octahedra, edges with two equivalent KSe6 octahedra, and an edgeedge with one SnSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–88°. There are a spread of Sn–Se bond distances ranging from 2.50–2.65 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to five K1+ and one Sn4+ atom to form a mixture of distorted corner and edge-sharing SeK5Sn octahedra. The corner-sharing octahedra tilt angles range from 2–60°. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two K1+ and two equivalent Sn4+ atoms. In the third Se2- site, Se2- is bonded to five K1+ and one Sn4+ atom to form a mixture of corner and edge-sharing SeK5Sn octahedra. The corner-sharing octahedra tilt angles range from 2–60°.