DOI: 10.17188/1679943
title: Materials Data on Yb2MgSe4 by Materials Project

description: MgYb2Se4 crystallizes in the triclinic P-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 corners with four YbSe6 octahedra, edges with two MgSe6 octahedra, and edges with seven YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–11°. There are a spread of Mg–Se bond distances ranging from 2.70–3.06 Å. In the second Mg2+ site, Mg2+ is bonded to six Se2- atoms to form distorted MgSe6 octahedra that share corners with two equivalent YbSe6 octahedra, edges with two MgSe6 octahedra, and edges with three YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 12–16°. There are a spread of Mg–Se bond distances ranging from 2.66–2.99 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 corners with four YbSe6 octahedra, edges with four MgSe6 octahedra, and edges with five YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–11°. There are a spread of Yb–Se bond distances ranging from 2.83–2.99 Å. In the second 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 2.92–3.21 Å. In the third Yb3+ site, Yb3+ is bonded to six Se2- atoms to form YbSe6 octahedra that share corners with two equivalent YbSe6 octahedra, corners with four MgSe6 octahedra, edges with three MgSe6 octahedra, and edges with six YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–16°. There are a spread of Yb–Se bond distances ranging from 2.88–3.00 Å. In the fourth Yb3+ site, Yb3+ is bonded to six Se2- atoms to form YbSe6 octahedra that share corners with two equivalent MgSe6 octahedra, corners with two equivalent YbSe6 octahedra, edges with three MgSe6 octahedra, and edges with six YbSe6 octahedra. The corner-sharing octahedra tilt angles range from 2–11°. There are a spread of Yb–Se bond distances ranging from 2.88–2.97 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to one Mg2+, three Yb3+, and one Se2- atom. The Se–Se bond length is 2.40 Å. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to two Mg2+, two equivalent Yb3+, and one Se2- atom. The Se–Se bond length is 2.45 Å. In the third Se2- site, Se2- is bonded to one Mg2+ and five Yb3+ atoms to form SeYb5Mg octahedra that share corners with two equivalent SeYb4Mg2 octahedra, corners with two equivalent SeYb4Mg square pyramids, edges with three SeYb5Mg octahedra, and edges with five SeYb3Mg2 square pyramids. The corner-sharing octahedra tilt angles range from 5–6°. In the fourth Se2- site, Se2- is bonded to two equivalent Mg2+ and three Yb3+ atoms to form SeYb3Mg2 square pyramids that share corners with two equivalent SeYb4Mg2 octahedra, corners with two equivalent SeYb4Mg square pyramids, edges with five SeYb5Mg octahedra, and edges with three SeYb3Mg2 square pyramids. The corner-sharing octahedra tilt angles range from 6–7°. In the fifth Se2- site, Se2- is bonded to one Mg2+ and four Yb3+ atoms to form SeYb4Mg square pyramids that share corners with two equivalent SeYb5Mg octahedra, corners with two equivalent SeYb3Mg2 square pyramids, edges with five SeYb5Mg octahedra, and edges with three SeYb3Mg2 square pyramids. The corner-sharing octahedral tilt angles are 9°. In the sixth Se2- site, Se2- is bonded to two Mg2+ and four Yb3+ atoms to form SeYb4Mg2 octahedra that share corners with two equivalent SeYb5Mg octahedra, corners with two equivalent SeYb3Mg2 square pyramids, edges with three SeYb5Mg octahedra, and edges with five SeYb3Mg2 square pyramids. The corner-sharing octahedra tilt angles range from 5–6°. In the seventh Se2- site, Se2- is bonded in a 5-coordinate geometry to one Mg2+, three Yb3+, and one Se2- atom. The Se–Se bond length is 2.44 Å. In the eighth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Mg2+, two Yb3+, and one Se2- atom.