Materials Data on Dy2MgSe4 by Materials Project

Abstract

MgDy2Se4 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 DySe6 octahedra, edges with four DySe6 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 2.67–2.77 Å. There are two inequivalent Dy3+ sites. In the first Dy3+ site, Dy3+ is bonded to six Se2- atoms to form DySe6 octahedra that share corners with three equivalent DySe6 octahedra, corners with two equivalent MgSe5 square pyramids, edges with six DySe6 octahedra, and an edgeedge with one MgSe5 square pyramid. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Dy–Se bond distances ranging from 2.83–2.95 Å. In the second Dy3+ site, Dy3+ is bonded to six Se2- atoms to form DySe6 octahedra that share corners with three equivalent DySe6 octahedra, corners with two equivalent MgSe5 square pyramids, edges with four DySe6 octahedra, and edges with three equivalent MgSe5 square pyramids. The corner-sharing octahedra tilt angles range from 54–57°. There are a spread of Dy–Se bond distances ranging from 2.77–2.96 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Mg2+ and two equivalent Dy3+ atoms to form a mixture of edge and corner-sharing SeDy2Mg3 square pyramids. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four Dy3+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Dy3+ atoms. In the fourth Se2- site, Se2- is bonded to two equivalent Mg2+ and three Dy3+ atoms to form SeDy3Mg2 square pyramids that share corners with two equivalent SeDy2Mg3 square pyramids and edges with five SeDy3Mg2 square pyramids.