MgSi2 crystallizes in the monoclinic P2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 13-coordinate geometry to three equivalent Mg(1), two equivalent Si(2), two equivalent Si(3), two equivalent Si(4), and four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 14-coordinate geometry to two equivalent Mg(2), two equivalent Si(1), two equivalent Si(3), four equivalent Si(2), and four equivalent Si(4) atoms. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), one Si(2), two equivalent Si(1), and two equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 11-coordinate geometry to two equivalent Mg(1), four equivalent Mg(2), one Si(1), one Si(4), and three equivalent Si(2) atoms. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), one Si(4), two equivalent Si(1), and three equivalent Si(3) atoms. In the fourth Si site, Si(4) is bonded in a 11-coordinate geometry to two equivalent Mg(1), four equivalent Mg(2), one Si(2), one Si(3), and three equivalent Si(4) atoms.
MgSi2 crystallizes in the monoclinic P2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 13-coordinate geometry to three equivalent Mg(1), two equivalent Si(2), two equivalent Si(3), two equivalent Si(4), and four equivalent Si(1) atoms. There are two shorter (2.78 Å) and one longer (3.04 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Si(2) bond lengths are 2.88 Å. Both Mg(1)-Si(3) bond lengths are 2.87 Å. Both Mg(1)-Si(4) bond lengths are 2.93 Å. All Mg(1)-Si(1) bond lengths are 2.91 Å. In the second Mg site, Mg(2) is bonded in a 14-coordinate geometry to two equivalent Mg(2), two equivalent Si(1), two equivalent Si(3), four equivalent Si(2), and four equivalent Si(4) atoms. Both Mg(2)-Mg(2) bond lengths are 2.78 Å. Both Mg(2)-Si(1) bond lengths are 2.91 Å. Both Mg(2)-Si(3) bond lengths are 2.95 Å. There are two shorter (2.91 Å) and two longer (3.02 Å) Mg(2)-Si(2) bond lengths. There are two shorter (2.91 Å) and two longer (2.92 Å) Mg(2)-Si(4) bond lengths. There are four inequivalent Si sites. In the first Si site, Si(1) is bonded in a 11-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), one Si(2), two equivalent Si(1), and two equivalent Si(3) atoms. The Si(1)-Si(2) bond length is 2.64 Å. Both Si(1)-Si(1) bond lengths are 2.78 Å. There is one shorter (2.64 Å) and one longer (2.81 Å) Si(1)-Si(3) bond length. In the second Si site, Si(2) is bonded in a 11-coordinate geometry to two equivalent Mg(1), four equivalent Mg(2), one Si(1), one Si(4), and three equivalent Si(2) atoms. The Si(2)-Si(4) bond length is 2.60 Å. There is one shorter (2.51 Å) and two longer (2.78 Å) Si(2)-Si(2) bond lengths. In the third Si site, Si(3) is bonded in a 10-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), one Si(4), two equivalent Si(1), and three equivalent Si(3) atoms. The Si(3)-Si(4) bond length is 2.62 Å. There is one shorter (2.50 Å) and two longer (2.78 Å) Si(3)-Si(3) bond lengths. In the fourth Si site, Si(4) is bonded in a 11-coordinate geometry to two equivalent Mg(1), four equivalent Mg(2), one Si(2), one Si(3), and three equivalent Si(4) atoms. There is one shorter (2.51 Å) and two longer (2.78 Å) Si(4)-Si(4) bond lengths.