Mg4Si3 crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 3-coordinate geometry to one Si(1), one Si(2), and two equivalent Si(3) atoms. In the third Mg site, Mg(3) is bonded in a 7-coordinate geometry to one Si(1), three equivalent Si(2), and three equivalent Si(3) atoms. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to one Si(3), three equivalent Si(1), and three equivalent Si(2) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(1), three equivalent Mg(4), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), three equivalent Mg(3), three equivalent Mg(4), and one Si(3) atom. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(2), three equivalent Mg(3), one Si(2), and one Si(3) atom.
Mg4Si3 crystallizes in the triclinic P-1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), and two equivalent Si(1) atoms. The Mg(1)-Si(2) bond length is 2.88 Å. The Mg(1)-Si(3) bond length is 3.09 Å. Both Mg(1)-Si(1) bond lengths are 2.78 Å. In the second Mg site, Mg(2) is bonded in a 3-coordinate geometry to one Si(1), one Si(2), and two equivalent Si(3) atoms. The Mg(2)-Si(1) bond length is 3.14 Å. The Mg(2)-Si(2) bond length is 2.78 Å. There is one shorter (2.77 Å) and one longer (2.84 Å) Mg(2)-Si(3) bond length. In the third Mg site, Mg(3) is bonded in a 7-coordinate geometry to one Si(1), three equivalent Si(2), and three equivalent Si(3) atoms. The Mg(3)-Si(1) bond length is 2.86 Å. There are two shorter (2.74 Å) and one longer (3.02 Å) Mg(3)-Si(2) bond length. There are a spread of Mg(3)-Si(3) bond distances ranging from 2.81-3.07 Å. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to one Si(3), three equivalent Si(1), and three equivalent Si(2) atoms. The Mg(4)-Si(3) bond length is 3.08 Å. There are a spread of Mg(4)-Si(1) bond distances ranging from 2.82-2.90 Å. There are a spread of Mg(4)-Si(2) bond distances ranging from 2.87-2.91 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(1), three equivalent Mg(4), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.50 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(2), three equivalent Mg(3), three equivalent Mg(4), and one Si(3) atom. The Si(2)-Si(3) bond length is 2.77 Å. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(2), three equivalent Mg(3), one Si(2), and one Si(3) atom. The Si(3)-Si(3) bond length is 2.43 Å.