Mg2Si3 is Magnesium tetraboride-like structured and 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 5-coordinate geometry to one Si(1), one Si(4), one Si(6), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 1-coordinate geometry to three equivalent Si(2), three equivalent Si(4), and three equivalent Si(5) atoms. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), one Si(5), and two equivalent Si(4) atoms. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(3), one Si(2), one Si(3), one Si(5), and one Si(6) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(3), three equivalent Mg(2), one Si(1), one Si(4), and three equivalent Si(5) atoms. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(3), one Mg(4), three equivalent Mg(1), one Si(1), and two equivalent Si(6) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(4), three equivalent Mg(2), and one Si(2) atom. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(3), one Mg(4), three equivalent Mg(2), one Si(1), and three equivalent Si(2) atoms. In the sixth Si site, Si(6) is bonded in a 6-coordinate geometry to one Mg(1), one Mg(3), one Si(1), one Si(6), and two equivalent Si(3) atoms.
Mg2Si3 is Magnesium tetraboride-like structured and 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 5-coordinate geometry to one Si(1), one Si(4), one Si(6), and three equivalent Si(3) atoms. The Mg(1)-Si(1) bond length is 3.20 Å. The Mg(1)-Si(4) bond length is 2.85 Å. The Mg(1)-Si(6) bond length is 2.92 Å. There are a spread of Mg(1)-Si(3) bond distances ranging from 2.74-2.89 Å. In the second Mg site, Mg(2) is bonded in a 1-coordinate geometry to three equivalent Si(2), three equivalent Si(4), and three equivalent Si(5) atoms. There are a spread of Mg(2)-Si(2) bond distances ranging from 2.97-3.17 Å. There are a spread of Mg(2)-Si(4) bond distances ranging from 2.75-3.15 Å. There are a spread of Mg(2)-Si(5) bond distances ranging from 2.89-3.19 Å. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), one Si(6), and two equivalent Si(1) atoms. The Mg(3)-Si(2) bond length is 2.80 Å. The Mg(3)-Si(3) bond length is 3.09 Å. The Mg(3)-Si(4) bond length is 2.79 Å. The Mg(3)-Si(5) bond length is 2.75 Å. The Mg(3)-Si(6) bond length is 2.77 Å. There is one shorter (2.74 Å) and one longer (3.07 Å) Mg(3)-Si(1) bond length. In the fourth Mg site, Mg(4) is bonded in a 5-coordinate geometry to one Si(1), one Si(3), one Si(5), and two equivalent Si(4) atoms. The Mg(4)-Si(1) bond length is 3.00 Å. The Mg(4)-Si(3) bond length is 2.88 Å. The Mg(4)-Si(5) bond length is 2.71 Å. There is one shorter (2.81 Å) and one longer (2.87 Å) Mg(4)-Si(4) bond length. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(4), two equivalent Mg(3), one Si(2), one Si(3), one Si(5), and one Si(6) atom. The Si(1)-Si(2) bond length is 2.54 Å. The Si(1)-Si(3) bond length is 2.62 Å. The Si(1)-Si(5) bond length is 2.81 Å. The Si(1)-Si(6) bond length is 2.46 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(3), three equivalent Mg(2), one Si(1), one Si(4), and three equivalent Si(5) atoms. The Si(2)-Si(4) bond length is 2.43 Å. There are a spread of Si(2)-Si(5) bond distances ranging from 2.47-2.51 Å. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(3), one Mg(4), three equivalent Mg(1), one Si(1), and two equivalent Si(6) atoms. There is one shorter (2.43 Å) and one longer (2.50 Å) Si(3)-Si(6) bond length. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), two equivalent Mg(4), three equivalent Mg(2), and one Si(2) atom. In the fifth Si site, Si(5) is bonded in a 9-coordinate geometry to one Mg(3), one Mg(4), three equivalent Mg(2), one Si(1), and three equivalent Si(2) atoms. In the sixth Si site, Si(6) is bonded in a 6-coordinate geometry to one Mg(1), one Mg(3), one Si(1), one Si(6), and two equivalent Si(3) atoms. The Si(6)-Si(6) bond length is 2.49 Å.