DOI: 10.17188/1665185
title: Materials Data on K4As2Se5 by Materials Project

description: K4As2Se5 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four 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 12–15°. There are a spread of K–Se bond distances ranging from 3.30–3.55 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 12–20°. There are a spread of K–Se bond distances ranging from 3.36–3.57 Å. In the third 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 8–15°. There are a spread of K–Se bond distances ranging from 3.38–3.42 Å. In the fourth 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 8–21°. There are a spread of K–Se bond distances ranging from 3.31–3.81 Å. There are two inequivalent As3+ sites. In the first As3+ site, As3+ is bonded in a trigonal non-coplanar geometry to three Se2- atoms. There are one shorter (2.37 Å) and two longer (2.38 Å) As–Se bond lengths. In the second As3+ site, As3+ is bonded in a water-like geometry to two Se2- atoms. There are one shorter (2.37 Å) and one longer (2.39 Å) As–Se bond lengths. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to five K1+ and one As3+ atom to form SeK5As octahedra that share corners with six SeK5As octahedra, a cornercorner with one SeK4As trigonal bipyramid, edges with nine SeK5As octahedra, and an edgeedge with one SeK4As trigonal bipyramid. The corner-sharing octahedra tilt angles range from 7–96°. In the second Se2- site, Se2- is bonded to five K1+ and one As3+ atom to form distorted SeK5As octahedra that share corners with six SeK5As octahedra, corners with two equivalent SeK4As trigonal bipyramids, edges with seven SeK5As octahedra, and edges with two equivalent SeK4As trigonal bipyramids. The corner-sharing octahedra tilt angles range from 9–96°. In the third Se2- site, Se2- is bonded to five K1+ and one As3+ atom to form distorted SeK5As octahedra that share corners with six SeK5As octahedra, corners with two equivalent SeK4As trigonal bipyramids, and edges with nine SeK5As octahedra. The corner-sharing octahedra tilt angles range from 9–97°. In the fourth Se2- site, Se2- is bonded to five K1+ and one As3+ atom to form distorted SeK5As octahedra that share corners with six SeK5As octahedra, a cornercorner with one SeK4As trigonal bipyramid, edges with seven SeK5As octahedra, and edges with three equivalent SeK4As trigonal bipyramids. The corner-sharing octahedra tilt angles range from 7–97°. In the fifth Se2- site, Se2- is bonded to four K1+ and one As3+ atom to form distorted SeK4As trigonal bipyramids that share corners with six SeK5As octahedra, corners with four equivalent SeK4As trigonal bipyramids, and edges with six SeK5As octahedra. The corner-sharing octahedra tilt angles range from 10–99°.