Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), and four equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent 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 7-coordinate geometry to one Mg(1), three equivalent Mg(2), one Si(1), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(1), three equivalent Mg(2), one Si(2), one Si(3), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), one Si(2), and one Si(3) atom.
Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(1), one Si(2), and four equivalent Si(3) atoms. The Mg(1)-Si(1) bond length is 2.66 Å. The Mg(1)-Si(2) bond length is 3.21 Å. There are a spread of Mg(1)-Si(3) bond distances ranging from 2.72-2.86 Å. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Si(3), three equivalent Si(1), and three equivalent Si(2) atoms. There is one shorter (2.81 Å) and one longer (2.86 Å) Mg(2)-Si(3) bond length. There are a spread of Mg(2)-Si(1) bond distances ranging from 2.74-3.01 Å. There are a spread of Mg(2)-Si(2) bond distances ranging from 2.85-2.96 Å. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Mg(1), three equivalent Mg(2), one Si(1), and two equivalent Si(2) atoms. The Si(1)-Si(1) bond length is 2.37 Å. There is one shorter (2.40 Å) and one longer (2.53 Å) Si(1)-Si(2) bond length. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(1), three equivalent Mg(2), one Si(2), one Si(3), and two equivalent Si(1) atoms. The Si(2)-Si(2) bond length is 2.66 Å. The Si(2)-Si(3) bond length is 2.48 Å. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), one Si(2), and one Si(3) atom. The Si(3)-Si(3) bond length is 2.53 Å.