Materials Data on Y2MgSe4 by Materials Project

Abstract

MgY2Se4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to four Se2- atoms to form MgSe4 trigonal pyramids that share corners with three equivalent YSe6 octahedra and a faceface with one YSe6 octahedra. The corner-sharing octahedra tilt angles range from 10–66°. There are a spread of Mg–Se bond distances ranging from 2.47–2.65 Å. There are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Y–Se bond distances ranging from 2.80–3.20 Å. In the second Y3+ site, Y3+ is bonded to six Se2- atoms to form distorted YSe6 octahedra that share corners with three equivalent MgSe4 trigonal pyramids, edges with two equivalent YSe6 octahedra, and a faceface with one MgSe4 trigonal pyramid. There are a spread of Y–Se bond distances ranging from 2.69–2.98 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to one Mg2+ and four Y3+ atoms. In the second Se2- site, Se2- is bonded in a T-shaped geometry to one Mg2+ and two Y3+ atoms. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Y3+ atoms.