Mg6SiC crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(1), and two equivalent C(1) atoms. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a distorted single-bond geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(1), and one C(1) atom. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. C(1) is bonded in a 6-coordinate geometry to two equivalent Mg(3) and four equivalent Mg(1) atoms.
Mg6SiC crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a distorted bent 120 degrees geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(1), and two equivalent C(1) atoms. There is one shorter (3.05 Å) and one longer (3.23 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(4) bond lengths are 2.91 Å. There is one shorter (3.12 Å) and one longer (3.15 Å) Mg(1)-Si(1) bond length. Both Mg(1)-C(1) bond lengths are 2.70 Å. In the second Mg site, Mg(2) is bonded in a 12-coordinate geometry to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Si(1) atoms. Both Mg(2)-Mg(4) bond lengths are 3.00 Å. All Mg(2)-Mg(3) bond lengths are 2.88 Å. Both Mg(2)-Si(1) bond lengths are 3.09 Å. In the third Mg site, Mg(3) is bonded in a distorted single-bond geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(1), and one C(1) atom. There is one shorter (3.09 Å) and one longer (3.17 Å) Mg(3)-Mg(4) bond length. Both Mg(3)-Si(1) bond lengths are 2.75 Å. The Mg(3)-C(1) bond length is 2.23 Å. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 10-coordinate geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. C(1) is bonded in a 6-coordinate geometry to two equivalent Mg(3) and four equivalent Mg(1) atoms.