Materials Data on K2TeSe3 by Materials Project
K2TeSe3 crystallizes in the monoclinic P2_1/c 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 a mixture of edge and corner-sharing KSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–15°. There are a spread of K–Se bond distances ranging from 3.37–3.40 Å. In the second K1+ site, K1+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing KSe6 octahedra. The corner-sharing octahedra tilt angles range from 12–23°. There are a spread of K–Se bond distances ranging from 3.39–3.83 Å. Te4+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.52 Å) and two longer (2.54 Å) Te–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to three K1+ and one Te4+ atom. In the second Se2- site, Se2- is bonded to five K1+ and one Te4+ atom to form SeK5Te octahedra that share corners with four equivalent SeK5Te octahedra, corners with two equivalent SeK4Te square pyramids, edges with four equivalent SeK5Te octahedra, and edges with three equivalent SeK4Te square pyramids. The corner-sharing octahedra tilt angles range from 10–15°. In the third Se2- site, Se2- is bonded to four K1+ and one Te4+ atom to form SeK4Te square pyramids that share corners with two equivalent SeK5Te octahedra, corners with two equivalent SeK4Te square pyramids, edges with three equivalent SeK5Te octahedra, and edges with two equivalent SeK4Te square pyramids. The corner-sharing octahedra tilt angles range from 5–87°.