Li2MgSi crystallizes in the cubic Fm-3m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one Li(2), three equivalent Li(3), one Si(3), and three equivalent Si(1) atoms. In the second Li site, Li(2) is bonded in a distorted body-centered cubic geometry to four equivalent Li(1) and four equivalent Mg(1) atoms. In the third Li site, Li(3) is bonded in a 9-coordinate geometry to four equivalent Li(1), four equivalent Mg(1), and one Si(3) atom. Mg(1) is bonded in a 8-coordinate geometry to one Li(2), three equivalent Li(3), one Si(2), and three equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a body-centered cubic geometry to four equivalent Li(1) and four equivalent Mg(1) atoms. In the second Si site, Si(2) is bonded in a body-centered cubic geometry to eight equivalent Mg(1) atoms. In the third Si site, Si(3) is bonded in a 14-coordinate geometry to six equivalent Li(3) and eight equivalent Li(1) atoms.
Li2MgSi crystallizes in the cubic Fm-3m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded in a 4-coordinate geometry to one Li(2), three equivalent Li(3), one Si(3), and three equivalent Si(1) atoms. The Li(1)-Li(2) bond length is 2.74 Å. All Li(1)-Li(3) bond lengths are 2.55 Å. The Li(1)-Si(3) bond length is 2.77 Å. All Li(1)-Si(1) bond lengths are 2.75 Å. In the second Li site, Li(2) is bonded in a distorted body-centered cubic geometry to four equivalent Li(1) and four equivalent Mg(1) atoms. All Li(2)-Mg(1) bond lengths are 2.74 Å. In the third Li site, Li(3) is bonded in a 9-coordinate geometry to four equivalent Li(1), four equivalent Mg(1), and one Si(3) atom. All Li(3)-Mg(1) bond lengths are 3.00 Å. The Li(3)-Si(3) bond length is 2.78 Å. Mg(1) is bonded in a 8-coordinate geometry to one Li(2), three equivalent Li(3), one Si(2), and three equivalent Si(1) atoms. The Mg(1)-Si(2) bond length is 2.77 Å. All Mg(1)-Si(1) bond lengths are 2.75 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a body-centered cubic geometry to four equivalent Li(1) and four equivalent Mg(1) atoms. In the second Si site, Si(2) is bonded in a body-centered cubic geometry to eight equivalent Mg(1) atoms. In the third Si site, Si(3) is bonded in a 14-coordinate geometry to six equivalent Li(3) and eight equivalent Li(1) atoms.