Mg2Si is Cotunnite structured and crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. Si(1) is bonded in a 8-coordinate geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms.
Mg2Si is Cotunnite structured and crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. There are a spread of Mg(1)-Si(1) bond distances ranging from 2.63-2.87 Å. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to four equivalent Si(1) atoms. There are a spread of Mg(2)-Si(1) bond distances ranging from 2.70-2.90 Å. Si(1) is bonded in a 8-coordinate geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms.