Mg2Si crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to two equivalent Si(1) and three equivalent Si(2) atoms. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to two equivalent Si(1) and three equivalent Si(2) atoms. In the fourth Mg site, Mg(4) is bonded in a distorted square co-planar geometry to four equivalent Si(1) atoms. In the fifth Mg site, Mg(5) is bonded in a square co-planar geometry to two equivalent Si(1) and two equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(2), three equivalent Mg(1), and three equivalent Mg(3) atoms.
Mg2Si crystallizes in the triclinic P-1 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to two equivalent Si(1) and three equivalent Si(2) atoms. There is one shorter (2.89 Å) and one longer (2.94 Å) Mg(1)-Si(1) bond length. There are a spread of Mg(1)-Si(2) bond distances ranging from 2.91-3.17 Å. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Si(1) and two equivalent Si(2) atoms. There is one shorter (2.73 Å) and one longer (2.77 Å) Mg(2)-Si(1) bond length. There is one shorter (2.63 Å) and one longer (2.64 Å) Mg(2)-Si(2) bond length. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to two equivalent Si(1) and three equivalent Si(2) atoms. There is one shorter (2.86 Å) and one longer (3.01 Å) Mg(3)-Si(1) bond length. There are a spread of Mg(3)-Si(2) bond distances ranging from 2.86-3.06 Å. In the fourth Mg site, Mg(4) is bonded in a distorted square co-planar geometry to four equivalent Si(1) atoms. There are two shorter (2.71 Å) and two longer (2.74 Å) Mg(4)-Si(1) bond lengths. In the fifth Mg site, Mg(5) is bonded in a square co-planar geometry to two equivalent Si(1) and two equivalent Si(2) atoms. Both Mg(5)-Si(1) bond lengths are 2.58 Å. Both Mg(5)-Si(2) bond lengths are 2.87 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), and two equivalent Mg(4) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(2), three equivalent Mg(1), and three equivalent Mg(3) atoms.