Materials Data on Ho2MgSe4 by Materials Project

Abstract

MgHo2Se4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to five Se2- atoms to form MgSe5 square pyramids that share corners with four HoSe6 octahedra, edges with four HoSe6 octahedra, and edges with four equivalent MgSe5 square pyramids. The corner-sharing octahedra tilt angles range from 3–4°. There are a spread of Mg–Se bond distances ranging from 2.67–2.76 Å. There are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with three equivalent HoSe6 octahedra, corners with two equivalent MgSe5 square pyramids, edges with six HoSe6 octahedra, and an edgeedge with one MgSe5 square pyramid. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Ho–Se bond distances ranging from 2.82–2.94 Å. In the second Ho3+ site, Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with three equivalent HoSe6 octahedra, corners with two equivalent MgSe5 square pyramids, edges with four HoSe6 octahedra, and edges with three equivalent MgSe5 square pyramids. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Ho–Se bond distances ranging from 2.76–2.95 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Mg2+ and two equivalent Ho3+ atoms to form a mixture of edge and corner-sharing SeHo2Mg3 square pyramids. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Ho3+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ho3+ atoms. In the fourth Se2- site, Se2- is bonded to two equivalent Mg2+ and three Ho3+ atoms to form SeHo3Mg2 square pyramids that share corners with two equivalent SeHo2Mg3 square pyramids and edges with five SeHo3Mg2 square pyramids.