DOI: 10.17188/1707567
title: Materials Data on Yb2MgSe4 by Materials Project

description: MgYb2Se4 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six Se2- atoms to form MgSe6 octahedra that share a cornercorner with one YbSe6 octahedra, corners with two equivalent MgSe6 octahedra, an edgeedge with one MgSe6 octahedra, and edges with four YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–74°. There are a spread of Mg–Se bond distances ranging from 2.59–3.00 Å. In the second Mg2+ site, Mg2+ is bonded to six Se2- atoms to form MgSe6 octahedra that share a cornercorner with one YbSe6 octahedra, corners with two equivalent MgSe6 octahedra, an edgeedge with one MgSe6 octahedra, and edges with four YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–74°. There are a spread of Mg–Se bond distances ranging from 2.61–2.93 Å. There are four inequivalent Yb3+ sites. In the first Yb3+ site, Yb3+ is bonded to six Se2- atoms to form YbSe6 octahedra that share a cornercorner with one MgSe6 octahedra, corners with two equivalent YbSe6 octahedra, an edgeedge with one YbSe6 octahedra, and edges with four MgSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–74°. There are a spread of Yb–Se bond distances ranging from 2.86–3.00 Å. In the second Yb3+ site, Yb3+ is bonded to six Se2- atoms to form YbSe6 octahedra that share a cornercorner with one MgSe6 octahedra, corners with two equivalent YbSe6 octahedra, an edgeedge with one YbSe6 octahedra, and edges with four MgSe6 octahedra. The corner-sharing octahedra tilt angles range from 4–74°. There are a spread of Yb–Se bond distances ranging from 2.88–3.03 Å. In the third Yb3+ site, Yb3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Yb–Se bond distances ranging from 2.88–3.24 Å. In the fourth Yb3+ site, Yb3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Yb–Se bond distances ranging from 2.87–3.46 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to two Mg2+ and three Yb3+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to two Mg2+ and three Yb3+ atoms. In the third Se2- site, Se2- is bonded to one Mg2+ and three Yb3+ atoms to form SeYb3Mg tetrahedra that share corners with six SeYb3Mg2 square pyramids, corners with two equivalent SeYb3Mg tetrahedra, and edges with two SeYb4Mg square pyramids. In the fourth Se2- site, Se2- is bonded to one Mg2+ and three Yb3+ atoms to form SeYb3Mg tetrahedra that share corners with six SeYb3Mg2 square pyramids, corners with two equivalent SeYb3Mg tetrahedra, and edges with two SeYb3Mg2 square pyramids. In the fifth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Mg2+ and four Yb3+ atoms. In the sixth Se2- site, Se2- is bonded to two Mg2+ and three Yb3+ atoms to form distorted SeYb3Mg2 square pyramids that share corners with four SeYb4Mg square pyramids, corners with two SeYb3Mg tetrahedra, edges with two SeYb4Mg square pyramids, and edges with two SeYb3Mg tetrahedra. In the seventh Se2- site, Se2- is bonded to one Mg2+ and four Yb3+ atoms to form distorted SeYb4Mg square pyramids that share corners with four SeYb3Mg2 square pyramids, corners with five SeYb3Mg tetrahedra, edges with two SeYb3Mg2 square pyramids, and an edgeedge with one SeYb3Mg tetrahedra. In the eighth Se2- site, Se2- is bonded to one Mg2+ and four Yb3+ atoms to form distorted SeYb4Mg square pyramids that share corners with four SeYb3Mg2 square pyramids, corners with five SeYb3Mg tetrahedra, edges with two SeYb3Mg2 square pyramids, and an edgeedge with one SeYb3Mg tetrahedra.