MgSi2 crystallizes in the triclinic P1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 14-coordinate geometry to one Mg(2), one Mg(4), one Si(3), one Si(6), two equivalent Si(1), two equivalent Si(8), three equivalent Si(2), and three equivalent Si(5) atoms. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(1), one Mg(3), one Si(2), one Si(4), two equivalent Si(7), three equivalent Si(1), and three equivalent Si(6) atoms. In the third Mg site, Mg(3) is bonded in a 14-coordinate geometry to one Mg(2), two equivalent Mg(4), one Si(1), one Si(3), one Si(8), two equivalent Si(6), three equivalent Si(4), and three equivalent Si(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to one Mg(1), two equivalent Mg(3), one Si(2), one Si(4), one Si(7), two equivalent Si(8), and three equivalent Si(3) atoms. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to one Mg(3), two equivalent Mg(1), three equivalent Mg(2), one Si(2), one Si(5), one Si(7), and two equivalent Si(6) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), one Mg(4), three equivalent Mg(1), one Si(1), one Si(8), and two equivalent Si(5) atoms. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), three equivalent Mg(4), one Si(7), and two equivalent Si(8) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(4), three equivalent Mg(3), one Si(6), and two equivalent Si(7) atoms. In the fifth Si site, Si(5) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(1), one Si(8), and two equivalent Si(2) atoms. In the sixth Si site, Si(6) is bonded in a 10-coordinate geometry to one Mg(1), two equivalent Mg(3), three equivalent Mg(2), one Si(4), one Si(7), and two equivalent Si(1) atoms. In the seventh Si site, Si(7) is bonded in a 11-coordinate geometry to one Mg(4), two equivalent Mg(2), three equivalent Mg(3), one Si(1), one Si(3), one Si(6), and two equivalent Si(4) atoms. In the eighth Si site, Si(8) is bonded in a 9-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(4), one Si(2), one Si(5), and two equivalent Si(3) atoms.
MgSi2 crystallizes in the triclinic P1 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 14-coordinate geometry to one Mg(2), one Mg(4), one Si(3), one Si(6), two equivalent Si(1), two equivalent Si(8), three equivalent Si(2), and three equivalent Si(5) atoms. The Mg(1)-Mg(2) bond length is 2.92 Å. The Mg(1)-Mg(4) bond length is 3.04 Å. The Mg(1)-Si(3) bond length is 2.93 Å. The Mg(1)-Si(6) bond length is 3.02 Å. There is one shorter (2.90 Å) and one longer (2.95 Å) Mg(1)-Si(1) bond length. There is one shorter (2.87 Å) and one longer (3.01 Å) Mg(1)-Si(8) bond length. There are a spread of Mg(1)-Si(2) bond distances ranging from 2.84-3.07 Å. There are a spread of Mg(1)-Si(5) bond distances ranging from 2.82-3.02 Å. In the second Mg site, Mg(2) is bonded in a 10-coordinate geometry to one Mg(1), one Mg(3), one Si(2), one Si(4), two equivalent Si(7), three equivalent Si(1), and three equivalent Si(6) atoms. The Mg(2)-Mg(3) bond length is 2.89 Å. The Mg(2)-Si(2) bond length is 2.70 Å. The Mg(2)-Si(4) bond length is 2.80 Å. There is one shorter (2.96 Å) and one longer (2.98 Å) Mg(2)-Si(7) bond length. There are a spread of Mg(2)-Si(1) bond distances ranging from 2.93-2.99 Å. There are a spread of Mg(2)-Si(6) bond distances ranging from 2.96-3.02 Å. In the third Mg site, Mg(3) is bonded in a 14-coordinate geometry to one Mg(2), two equivalent Mg(4), one Si(1), one Si(3), one Si(8), two equivalent Si(6), three equivalent Si(4), and three equivalent Si(7) atoms. There is one shorter (3.06 Å) and one longer (3.07 Å) Mg(3)-Mg(4) bond length. The Mg(3)-Si(1) bond length is 3.15 Å. The Mg(3)-Si(3) bond length is 2.76 Å. The Mg(3)-Si(8) bond length is 3.10 Å. Both Mg(3)-Si(6) bond lengths are 2.95 Å. There are a spread of Mg(3)-Si(4) bond distances ranging from 2.88-2.96 Å. There are a spread of Mg(3)-Si(7) bond distances ranging from 2.94-3.01 Å. In the fourth Mg site, Mg(4) is bonded in a 7-coordinate geometry to one Mg(1), two equivalent Mg(3), one Si(2), one Si(4), one Si(7), two equivalent Si(8), and three equivalent Si(3) atoms. The Mg(4)-Si(2) bond length is 2.74 Å. The Mg(4)-Si(4) bond length is 2.69 Å. The Mg(4)-Si(7) bond length is 3.23 Å. There is one shorter (2.85 Å) and one longer (2.87 Å) Mg(4)-Si(8) bond length. There are a spread of Mg(4)-Si(3) bond distances ranging from 2.77-3.07 Å. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to one Mg(3), two equivalent Mg(1), three equivalent Mg(2), one Si(2), one Si(5), one Si(7), and two equivalent Si(6) atoms. The Si(1)-Si(2) bond length is 2.59 Å. The Si(1)-Si(5) bond length is 2.70 Å. The Si(1)-Si(7) bond length is 2.79 Å. There is one shorter (2.70 Å) and one longer (2.71 Å) Si(1)-Si(6) bond length. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), one Mg(4), three equivalent Mg(1), one Si(1), one Si(8), and two equivalent Si(5) atoms. The Si(2)-Si(8) bond length is 2.48 Å. Both Si(2)-Si(5) bond lengths are 2.55 Å. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), three equivalent Mg(4), one Si(7), and two equivalent Si(8) atoms. The Si(3)-Si(7) bond length is 2.51 Å. There is one shorter (2.71 Å) and one longer (2.72 Å) Si(3)-Si(8) bond length. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(2), one Mg(4), three equivalent Mg(3), one Si(6), and two equivalent Si(7) atoms. The Si(4)-Si(6) bond length is 2.47 Å. There is one shorter (2.53 Å) and one longer (2.60 Å) Si(4)-Si(7) bond length. In the fifth Si site, Si(5) is bonded in a 7-coordinate geometry to three equivalent Mg(1), one Si(1), one Si(8), and two equivalent Si(2) atoms. The Si(5)-Si(8) bond length is 2.58 Å. In the sixth Si site, Si(6) is bonded in a 10-coordinate geometry to one Mg(1), two equivalent Mg(3), three equivalent Mg(2), one Si(4), one Si(7), and two equivalent Si(1) atoms. The Si(6)-Si(7) bond length is 2.52 Å. In the seventh Si site, Si(7) is bonded in a 11-coordinate geometry to one Mg(4), two equivalent Mg(2), three equivalent Mg(3), one Si(1), one Si(3), one Si(6), and two equivalent Si(4) atoms. In the eighth Si site, Si(8) is bonded in a 9-coordinate geometry to one Mg(3), two equivalent Mg(1), two equivalent Mg(4), one Si(2), one Si(5), and two equivalent Si(3) atoms.