Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic Cm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 9-coordinate geometry to one Si(1), two equivalent Si(10), three equivalent Si(11), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one Si(2), two equivalent Si(4), two equivalent Si(5), and three equivalent Si(12) atoms. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to one Si(11), two equivalent Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to one Si(12), two equivalent Si(1), two equivalent Si(4), and three equivalent Si(2) atoms. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to one Si(7), two equivalent Si(12), two equivalent Si(9), and three equivalent Si(5) atoms. In the sixth Mg site, Mg(6) is bonded in a 8-coordinate geometry to one Si(11), one Si(8), three equivalent Si(10), and three equivalent Si(6) atoms. In the seventh Mg site, Mg(7) is bonded in a 6-coordinate geometry to one Si(9), two equivalent Si(8), and three equivalent Si(7) atoms. In the eighth Mg site, Mg(8) is bonded in a 7-coordinate geometry to two equivalent Si(6), two equivalent Si(7), and three equivalent Si(8) atoms. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(4), three equivalent Mg(3), one Si(2), and two equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), three equivalent Mg(4), one Si(1), and two equivalent Si(4) atoms. In the third Si site, Si(3) is bonded in a distorted q6 geometry to two equivalent Mg(3), three equivalent Mg(1), two equivalent Si(1), and two equivalent Si(11) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(12), and two equivalent Si(2) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent Mg(2), three equivalent Mg(5), one Si(12), and two equivalent Si(9) atoms. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to two equivalent Mg(8), three equivalent Mg(6), one Si(8), and two equivalent Si(10) atoms. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(8), three equivalent Mg(7), one Si(8), and two equivalent Si(9) atoms. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Mg(6), two equivalent Mg(7), three equivalent Mg(8), one Si(6), and one Si(7) atom. 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 8-coordinate geometry to two equivalent Mg(1), three equivalent Mg(6), one Si(11), and two equivalent Si(6) atoms. In the eleventh Si site, Si(11) is bonded in a 8-coordinate geometry to one Mg(3), one Mg(6), three equivalent Mg(1), one Si(10), and two equivalent Si(3) atoms. In the twelfth Si site, Si(12) is bonded in a 9-coordinate geometry to one Mg(4), two equivalent Mg(5), three equivalent Mg(2), one Si(5), and two equivalent Si(4) atoms.
Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic Cm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 9-coordinate geometry to one Si(1), two equivalent Si(10), three equivalent Si(11), and three equivalent Si(3) atoms. The Mg(1)-Si(1) bond length is 2.74 Å. Both Mg(1)-Si(10) bond lengths are 3.03 Å. There is one shorter (2.80 Å) and two longer (2.88 Å) Mg(1)-Si(11) bond lengths. There is one shorter (2.98 Å) and two longer (3.03 Å) Mg(1)-Si(3) bond lengths. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one Si(2), two equivalent Si(4), two equivalent Si(5), and three equivalent Si(12) atoms. The Mg(2)-Si(2) bond length is 2.82 Å. Both Mg(2)-Si(4) bond lengths are 2.99 Å. Both Mg(2)-Si(5) bond lengths are 3.00 Å. There are two shorter (2.82 Å) and one longer (2.83 Å) Mg(2)-Si(12) bond length. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to one Si(11), two equivalent Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. The Mg(3)-Si(11) bond length is 3.00 Å. Both Mg(3)-Si(2) bond lengths are 2.88 Å. Both Mg(3)-Si(3) bond lengths are 2.97 Å. There is one shorter (2.77 Å) and two longer (2.86 Å) Mg(3)-Si(1) bond lengths. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to one Si(12), two equivalent Si(1), two equivalent Si(4), and three equivalent Si(2) atoms. The Mg(4)-Si(12) bond length is 2.80 Å. Both Mg(4)-Si(1) bond lengths are 2.88 Å. Both Mg(4)-Si(4) bond lengths are 3.00 Å. There is one shorter (2.80 Å) and two longer (2.85 Å) Mg(4)-Si(2) bond lengths. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to one Si(7), two equivalent Si(12), two equivalent Si(9), and three equivalent Si(5) atoms. The Mg(5)-Si(7) bond length is 3.14 Å. Both Mg(5)-Si(12) bond lengths are 2.87 Å. Both Mg(5)-Si(9) bond lengths are 2.85 Å. There are two shorter (2.80 Å) and one longer (2.86 Å) Mg(5)-Si(5) bond length. In the sixth Mg site, Mg(6) is bonded in a 8-coordinate geometry to one Si(11), one Si(8), three equivalent Si(10), and three equivalent Si(6) atoms. The Mg(6)-Si(11) bond length is 2.85 Å. The Mg(6)-Si(8) bond length is 3.06 Å. There are two shorter (2.86 Å) and one longer (2.92 Å) Mg(6)-Si(10) bond length. There are two shorter (2.90 Å) and one longer (2.96 Å) Mg(6)-Si(6) bond length. In the seventh Mg site, Mg(7) is bonded in a 6-coordinate geometry to one Si(9), two equivalent Si(8), and three equivalent Si(7) atoms. The Mg(7)-Si(9) bond length is 2.67 Å. Both Mg(7)-Si(8) bond lengths are 2.73 Å. There is one shorter (2.68 Å) and two longer (2.96 Å) Mg(7)-Si(7) bond lengths. In the eighth Mg site, Mg(8) is bonded in a 7-coordinate geometry to two equivalent Si(6), two equivalent Si(7), and three equivalent Si(8) atoms. Both Mg(8)-Si(6) bond lengths are 2.90 Å. Both Mg(8)-Si(7) bond lengths are 2.82 Å. There is one shorter (2.78 Å) and two longer (2.86 Å) Mg(8)-Si(8) bond lengths. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(4), three equivalent Mg(3), one Si(2), and two equivalent Si(3) atoms. The Si(1)-Si(2) bond length is 2.38 Å. Both Si(1)-Si(3) bond lengths are 2.64 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), three equivalent Mg(4), one Si(1), and two equivalent Si(4) atoms. Both Si(2)-Si(4) bond lengths are 2.54 Å. In the third Si site, Si(3) is bonded in a distorted q6 geometry to two equivalent Mg(3), three equivalent Mg(1), two equivalent Si(1), and two equivalent Si(11) atoms. Both Si(3)-Si(11) bond lengths are 2.48 Å. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(12), and two equivalent Si(2) atoms. Both Si(4)-Si(12) bond lengths are 2.53 Å. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent Mg(2), three equivalent Mg(5), one Si(12), and two equivalent Si(9) atoms. The Si(5)-Si(12) bond length is 2.41 Å. Both Si(5)-Si(9) bond lengths are 2.54 Å. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to two equivalent Mg(8), three equivalent Mg(6), one Si(8), and two equivalent Si(10) atoms. The Si(6)-Si(8) bond length is 2.41 Å. Both Si(6)-Si(10) bond lengths are 2.50 Å. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(8), three equivalent Mg(7), one Si(8), and two equivalent Si(9) atoms. The Si(7)-Si(8) bond length is 2.48 Å. Both Si(7)-Si(9) bond lengths are 2.51 Å. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Mg(6), two equivalent Mg(7), three equivalent Mg(8), one Si(6), and one Si(7) atom. 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 8-coordinate geometry to two equivalent Mg(1), three equivalent Mg(6), one Si(11), and two equivalent Si(6) atoms. The Si(10)-Si(11) bond length is 2.41 Å. In the eleventh Si site, Si(11) is bonded in a 8-coordinate geometry to one Mg(3), one Mg(6), three equivalent Mg(1), one Si(10), and two equivalent Si(3) atoms. In the twelfth Si site, Si(12) is bonded in a 9-coordinate geometry to one Mg(4), two equivalent Mg(5), three equivalent Mg(2), one Si(5), and two equivalent Si(4) atoms.