Materials Data on Mg2Be3Tl2F12 by Materials Project

Abstract

Mg2Be3Tl2F12 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six F1- atoms to form MgF6 octahedra that share corners with six equivalent BeF4 tetrahedra. There are three shorter (2.00 Å) and three longer (2.02 Å) Mg–F bond lengths. In the second Mg2+ site, Mg2+ is bonded to six F1- atoms to form MgF6 octahedra that share corners with six equivalent BeF4 tetrahedra. There are three shorter (2.01 Å) and three longer (2.03 Å) Mg–F bond lengths. Be2+ is bonded to four F1- atoms to form BeF4 tetrahedra that share corners with four MgF6 octahedra. The corner-sharing octahedra tilt angles range from 14–47°. There are a spread of Be–F bond distances ranging from 1.56–1.58 Å. There are two inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Tl–F bond distances ranging from 2.87–3.26 Å. In the second Tl1+ site, Tl1+ is bonded in a 12-coordinate geometry to twelve F1- atoms. There are a spread of Tl–F bond distances ranging from 2.93–3.22 Å. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Mg2+, one Be2+, and one Tl1+ atom. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one Mg2+, one Be2+, and three Tl1+ atoms. In the third F1- site, F1- is bonded in a distorted linear geometry to one Mg2+, one Be2+, and two Tl1+ atoms. In the fourth F1- site, F1- is bonded in a 2-coordinate geometry to one Mg2+, one Be2+, and one Tl1+ atom.