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 6-coordinate geometry to three equivalent Si(2) and three equivalent Si(5) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Si(6), three equivalent Si(1), and three equivalent Si(2) atoms. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to one Si(1), one Si(3), two equivalent Si(6), two equivalent Si(8), three equivalent Si(4), and three equivalent Si(7) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to two equivalent Si(8), three equivalent Si(3), and three equivalent Si(5) atoms. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(3), three equivalent Mg(2), two equivalent Si(7), and three equivalent Si(6) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), and two equivalent Si(5) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(3), three equivalent Mg(4), two equivalent Si(4), and three equivalent Si(8) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to three equivalent Mg(3), two equivalent Si(3), and three equivalent Si(8) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to three equivalent Mg(1), three equivalent Mg(4), and two equivalent Si(2) atoms. In the sixth Si site, Si(6) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), three equivalent Si(1), and three equivalent Si(7) atoms. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to three equivalent Mg(3), two equivalent Si(1), and three equivalent Si(6) atoms. In the eighth Si site, Si(8) is bonded in a 10-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), three equivalent Si(3), and three equivalent Si(4) 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 6-coordinate geometry to three equivalent Si(2) and three equivalent Si(5) atoms. There are a spread of Mg(1)-Si(2) bond distances ranging from 2.58-2.80 Å. There are a spread of Mg(1)-Si(5) bond distances ranging from 2.58-2.80 Å. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to two equivalent Si(6), three equivalent Si(1), and three equivalent Si(2) atoms. There is one shorter (2.89 Å) and one longer (2.95 Å) Mg(2)-Si(6) bond length. There are a spread of Mg(2)-Si(1) bond distances ranging from 2.88-3.07 Å. There are a spread of Mg(2)-Si(2) bond distances ranging from 2.87-3.09 Å. In the third Mg site, Mg(3) is bonded in a 10-coordinate geometry to one Si(1), one Si(3), two equivalent Si(6), two equivalent Si(8), three equivalent Si(4), and three equivalent Si(7) atoms. The Mg(3)-Si(1) bond length is 3.13 Å. The Mg(3)-Si(3) bond length is 3.13 Å. There is one shorter (2.86 Å) and one longer (2.88 Å) Mg(3)-Si(6) bond length. There is one shorter (2.86 Å) and one longer (2.88 Å) Mg(3)-Si(8) bond length. There are a spread of Mg(3)-Si(4) bond distances ranging from 2.71-2.95 Å. There are a spread of Mg(3)-Si(7) bond distances ranging from 2.70-2.95 Å. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to two equivalent Si(8), three equivalent Si(3), and three equivalent Si(5) atoms. There is one shorter (2.89 Å) and one longer (2.95 Å) Mg(4)-Si(8) bond length. There are a spread of Mg(4)-Si(3) bond distances ranging from 2.89-3.07 Å. There are a spread of Mg(4)-Si(5) bond distances ranging from 2.88-3.08 Å. There are eight inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(3), three equivalent Mg(2), two equivalent Si(7), and three equivalent Si(6) atoms. There is one shorter (2.52 Å) and one longer (2.53 Å) Si(1)-Si(7) bond length. There are a spread of Si(1)-Si(6) bond distances ranging from 2.57-2.70 Å. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to three equivalent Mg(1), three equivalent Mg(2), and two equivalent Si(5) atoms. There is one shorter (2.48 Å) and one longer (2.53 Å) Si(2)-Si(5) bond length. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to one Mg(3), three equivalent Mg(4), two equivalent Si(4), and three equivalent Si(8) atoms. There is one shorter (2.52 Å) and one longer (2.53 Å) Si(3)-Si(4) bond length. There are a spread of Si(3)-Si(8) bond distances ranging from 2.57-2.70 Å. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to three equivalent Mg(3), two equivalent Si(3), and three equivalent Si(8) atoms. There are a spread of Si(4)-Si(8) bond distances ranging from 2.62-2.85 Å. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to three equivalent Mg(1), three equivalent Mg(4), and two equivalent Si(2) atoms. In the sixth Si site, Si(6) is bonded in a 10-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), three equivalent Si(1), and three equivalent Si(7) atoms. There are a spread of Si(6)-Si(7) bond distances ranging from 2.62-2.86 Å. In the seventh Si site, Si(7) is bonded in a 8-coordinate geometry to three equivalent Mg(3), two equivalent Si(1), and three equivalent Si(6) atoms. In the eighth Si site, Si(8) is bonded in a 10-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), three equivalent Si(3), and three equivalent Si(4) atoms.