Materials Data on KHo2CuSe4 by Materials Project
KHo2CuSe4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to eight Se2- atoms. There are a spread of K–Se bond distances ranging from 3.21–3.92 Å. Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with three equivalent HoSe6 octahedra, a cornercorner with one CuSe4 tetrahedra, edges with five equivalent HoSe6 octahedra, and edges with two equivalent CuSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 0–41°. There are a spread of Ho–Se bond distances ranging from 2.83–2.94 Å. Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with two equivalent HoSe6 octahedra, corners with two equivalent CuSe4 tetrahedra, and edges with four equivalent HoSe6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are two shorter (2.46 Å) and two longer (2.47 Å) Cu–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to two equivalent K1+, two equivalent Ho3+, and two equivalent Cu1+ atoms. In the second Se2- site, Se2- is bonded to two equivalent K1+, three equivalent Ho3+, and one Cu1+ atom to form a mixture of distorted edge, corner, and face-sharing SeK2Ho3Cu octahedra. The corner-sharing octahedral tilt angles are 62°. In the third Se2- site, Se2- is bonded in a distorted square co-planar geometry to two equivalent K1+ and four equivalent Ho3+ atoms.