Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(10), and two equivalent Si(6) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to one Si(2), one Si(5), two equivalent Si(12), and two equivalent Si(4) atoms. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(6), and two equivalent Si(11) atoms. In the fourth Mg site, Mg(4) is bonded in a 9-coordinate geometry to one Si(11), one Si(12), one Si(3), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. In the fifth Mg site, Mg(5) is bonded in a 6-coordinate geometry to one Si(12), one Si(4), one Si(5), one Si(7), and two equivalent Si(9) atoms. In the sixth Mg site, Mg(6) is bonded in a distorted rectangular see-saw-like geometry to one Si(10), one Si(11), and two equivalent Si(6) atoms. In the seventh Mg site, Mg(7) is bonded in a 4-coordinate geometry to one Si(5), one Si(8), one Si(9), and two equivalent Si(7) atoms. In the eighth Mg site, Mg(8) is bonded in a 6-coordinate geometry to one Si(10), one Si(7), two equivalent Si(6), and two equivalent Si(8) atoms. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to two equivalent Mg(4), one Si(11), one Si(4), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(4), one Si(3), and two equivalent Si(1) atoms. In the third Si site, Si(3) is bonded in a 1-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Si(2), and two equivalent Si(11) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(5), two equivalent Mg(2), two equivalent Mg(4), one Si(1), and two equivalent Si(12) atoms. In the fifth Si site, Si(5) is bonded in a 7-coordinate geometry to one Mg(2), one Mg(5), one Mg(7), two equivalent Si(12), and two equivalent Si(9) atoms. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(6), two equivalent Mg(8), and one Si(10) atom. In the seventh Si site, Si(7) is bonded in a 7-coordinate geometry to one Mg(5), one Mg(8), two equivalent Mg(7), one Si(8), and two equivalent Si(9) atoms. In the eighth Si site, Si(8) is bonded in a 6-coordinate geometry to one Mg(7), two equivalent Mg(8), one Si(7), and two equivalent Si(10) atoms. In the ninth Si site, Si(9) is bonded in a 7-coordinate geometry to one Mg(7), two equivalent Mg(5), two equivalent Si(5), and two equivalent Si(7) atoms. In the tenth Si site, Si(10) is bonded in a 7-coordinate geometry to one Mg(6), one Mg(8), two equivalent Mg(1), one Si(6), and two equivalent Si(8) atoms. In the eleventh Si site, Si(11) is bonded in a 7-coordinate geometry to one Mg(4), one Mg(6), two equivalent Mg(3), one Si(1), and two equivalent Si(3) atoms. In the twelfth Si site, Si(12) is bonded in a 8-coordinate geometry to one Mg(4), one Mg(5), two equivalent Mg(2), two equivalent Si(4), and two equivalent Si(5) atoms.
Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(3), two equivalent Si(10), and two equivalent Si(6) atoms. The Mg(1)-Si(3) bond length is 2.72 Å. There is one shorter (2.72 Å) and one longer (2.75 Å) Mg(1)-Si(10) bond length. There is one shorter (2.70 Å) and one longer (2.71 Å) Mg(1)-Si(6) bond length. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to one Si(2), one Si(5), two equivalent Si(12), and two equivalent Si(4) atoms. The Mg(2)-Si(2) bond length is 2.74 Å. The Mg(2)-Si(5) bond length is 2.84 Å. There is one shorter (2.82 Å) and one longer (2.90 Å) Mg(2)-Si(12) bond length. There is one shorter (2.90 Å) and one longer (2.99 Å) Mg(2)-Si(4) bond length. In the third Mg site, Mg(3) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(6), and two equivalent Si(11) atoms. The Mg(3)-Si(2) bond length is 2.72 Å. The Mg(3)-Si(3) bond length is 2.99 Å. The Mg(3)-Si(6) bond length is 2.98 Å. There is one shorter (2.78 Å) and one longer (2.81 Å) Mg(3)-Si(11) bond length. In the fourth Mg site, Mg(4) is bonded in a 9-coordinate geometry to one Si(11), one Si(12), one Si(3), two equivalent Si(1), two equivalent Si(2), and two equivalent Si(4) atoms. The Mg(4)-Si(11) bond length is 2.95 Å. The Mg(4)-Si(12) bond length is 2.74 Å. The Mg(4)-Si(3) bond length is 2.93 Å. Both Mg(4)-Si(1) bond lengths are 2.92 Å. There is one shorter (2.80 Å) and one longer (3.04 Å) Mg(4)-Si(2) bond length. There is one shorter (3.03 Å) and one longer (3.05 Å) Mg(4)-Si(4) bond length. In the fifth Mg site, Mg(5) is bonded in a 6-coordinate geometry to one Si(12), one Si(4), one Si(5), one Si(7), and two equivalent Si(9) atoms. The Mg(5)-Si(12) bond length is 2.69 Å. The Mg(5)-Si(4) bond length is 3.01 Å. The Mg(5)-Si(5) bond length is 2.93 Å. The Mg(5)-Si(7) bond length is 2.92 Å. There is one shorter (2.74 Å) and one longer (2.82 Å) Mg(5)-Si(9) bond length. In the sixth Mg site, Mg(6) is bonded in a distorted rectangular see-saw-like geometry to one Si(10), one Si(11), and two equivalent Si(6) atoms. The Mg(6)-Si(10) bond length is 2.84 Å. The Mg(6)-Si(11) bond length is 2.77 Å. There is one shorter (2.70 Å) and one longer (2.77 Å) Mg(6)-Si(6) bond length. In the seventh Mg site, Mg(7) is bonded in a 4-coordinate geometry to one Si(5), one Si(8), one Si(9), and two equivalent Si(7) atoms. The Mg(7)-Si(5) bond length is 2.75 Å. The Mg(7)-Si(8) bond length is 2.78 Å. The Mg(7)-Si(9) bond length is 3.16 Å. There is one shorter (2.93 Å) and one longer (2.97 Å) Mg(7)-Si(7) bond length. In the eighth Mg site, Mg(8) is bonded in a 6-coordinate geometry to one Si(10), one Si(7), two equivalent Si(6), and two equivalent Si(8) atoms. The Mg(8)-Si(10) bond length is 2.85 Å. The Mg(8)-Si(7) bond length is 2.74 Å. There is one shorter (2.77 Å) and one longer (2.80 Å) Mg(8)-Si(6) bond length. There is one shorter (2.94 Å) and one longer (3.10 Å) Mg(8)-Si(8) bond length. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 6-coordinate geometry to two equivalent Mg(4), one Si(11), one Si(4), and two equivalent Si(2) atoms. The Si(1)-Si(11) bond length is 2.49 Å. The Si(1)-Si(4) bond length is 2.47 Å. There is one shorter (2.40 Å) and one longer (2.47 Å) Si(1)-Si(2) bond length. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(4), one Si(3), and two equivalent Si(1) atoms. The Si(2)-Si(3) bond length is 2.68 Å. In the third Si site, Si(3) is bonded in a 1-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Si(2), and two equivalent Si(11) atoms. There is one shorter (2.38 Å) and one longer (2.45 Å) Si(3)-Si(11) bond length. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(5), two equivalent Mg(2), two equivalent Mg(4), one Si(1), and two equivalent Si(12) atoms. There is one shorter (2.51 Å) and one longer (2.53 Å) Si(4)-Si(12) bond length. In the fifth Si site, Si(5) is bonded in a 7-coordinate geometry to one Mg(2), one Mg(5), one Mg(7), two equivalent Si(12), and two equivalent Si(9) atoms. There is one shorter (2.58 Å) and one longer (2.61 Å) Si(5)-Si(12) bond length. There is one shorter (2.64 Å) and one longer (2.69 Å) Si(5)-Si(9) bond length. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(6), two equivalent Mg(8), and one Si(10) atom. The Si(6)-Si(10) bond length is 2.46 Å. In the seventh Si site, Si(7) is bonded in a 7-coordinate geometry to one Mg(5), one Mg(8), two equivalent Mg(7), one Si(8), and two equivalent Si(9) atoms. The Si(7)-Si(8) bond length is 2.42 Å. There is one shorter (2.44 Å) and one longer (2.46 Å) Si(7)-Si(9) bond length. In the eighth Si site, Si(8) is bonded in a 6-coordinate geometry to one Mg(7), two equivalent Mg(8), one Si(7), and two equivalent Si(10) atoms. There is one shorter (2.37 Å) and one longer (2.39 Å) Si(8)-Si(10) bond length. In the ninth Si site, Si(9) is bonded in a 7-coordinate geometry to one Mg(7), two equivalent Mg(5), two equivalent Si(5), and two equivalent Si(7) atoms. In the tenth Si site, Si(10) is bonded in a 7-coordinate geometry to one Mg(6), one Mg(8), two equivalent Mg(1), one Si(6), and two equivalent Si(8) atoms. In the eleventh Si site, Si(11) is bonded in a 7-coordinate geometry to one Mg(4), one Mg(6), two equivalent Mg(3), one Si(1), and two equivalent Si(3) atoms. In the twelfth Si site, Si(12) is bonded in a 8-coordinate geometry to one Mg(4), one Mg(5), two equivalent Mg(2), two equivalent Si(4), and two equivalent Si(5) atoms.