Materials Data on SrMg2 by Materials Project

Abstract

Mg2Sr crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Mg2Sr sheet oriented in the (0, 0, 1) direction. Sr is bonded in a 12-coordinate geometry to three equivalent Mg atoms. All Sr–Mg bond lengths are 3.59 Å. There are two inequivalent Mg sites. In the first Mg site, Mg is bonded to six Mg atoms to form distorted MgMg6 pentagonal pyramids that share corners with six equivalent MgSr3Mg3 pentagonal pyramids, edges with six equivalent MgMg6 pentagonal pyramids, and a faceface with one MgSr3Mg3 pentagonal pyramid. There are three shorter (3.04 Å) and three longer (3.10 Å) Mg–Mg bond lengths. In the second Mg site, Mg is bonded to three equivalent Sr and three equivalent Mg atoms to form distorted MgSr3Mg3 pentagonal pyramids that share corners with six equivalent MgMg6 pentagonal pyramids, edges with six equivalent MgSr3Mg3 pentagonal pyramids, and a faceface with one MgMg6 pentagonal pyramid.