Materials Data on Mg2(AlSi2)3 by Materials Project

Abstract

Mg2(AlSi2)3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mg is bonded in a 12-coordinate geometry to two equivalent Mg, two Al, and eight Si atoms. Both Mg–Mg bond lengths are 2.98 Å. There are one shorter (2.73 Å) and one longer (3.09 Å) Mg–Al bond lengths. There are a spread of Mg–Si bond distances ranging from 2.77–2.95 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 11-coordinate geometry to one Mg, two Al, and eight Si atoms. There are one shorter (2.90 Å) and one longer (2.91 Å) Al–Al bond lengths. There are a spread of Al–Si bond distances ranging from 2.68–2.84 Å. In the second Al site, Al is bonded in a 6-coordinate geometry to two equivalent Mg, two equivalent Al, and four equivalent Si atoms. All Al–Si bond lengths are 2.82 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded in a 9-coordinate geometry to three equivalent Mg, two equivalent Al, and four Si atoms. There are a spread of Si–Si bond distances ranging from 2.49–2.70 Å. In the second Si site, Si is bonded in a 10-coordinate geometry to two equivalent Mg, six Al, and two Si atoms. The Si–Si bond length is 2.73 Å. In the third Si site, Si is bonded in a 8-coordinate geometry to three equivalent Mg, two equivalent Al, and three equivalent Si atoms.