Mg6SnSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Si(1) atoms to form distorted MgMg8Si2Sn2 cuboctahedra that share corners with ten equivalent Mg(1)Mg8Si2Sn2 cuboctahedra, edges with two equivalent Mg(1)Mg8Si2Sn2 cuboctahedra, edges with four equivalent Mg(4)Mg4Si2 cuboctahedra, and faces with four equivalent Mg(1)Mg8Si2Sn2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a distorted linear geometry to four equivalent Mg(1) and two equivalent Sn(1) atoms. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent Mg(1), two equivalent Sn(1), and one Si(1) atom. In the fourth Mg site, Mg(4) is bonded to four equivalent Mg(1) and two equivalent Si(1) atoms to form distorted MgMg4Si2 cuboctahedra that share corners with two equivalent Mg(4)Mg4Si2 cuboctahedra, edges with two equivalent Mg(4)Mg4Si2 cuboctahedra, and edges with eight equivalent Mg(1)Mg8Si2Sn2 cuboctahedra. Sn(1) is bonded in a distorted q6 geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.
Mg6SnSi crystallizes in the orthorhombic Amm2 space group. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), two equivalent Sn(1), and two equivalent Si(1) atoms to form distorted MgMg8Si2Sn2 cuboctahedra that share corners with ten equivalent Mg(1)Mg8Si2Sn2 cuboctahedra, edges with two equivalent Mg(1)Mg8Si2Sn2 cuboctahedra, edges with four equivalent Mg(4)Mg4Si2 cuboctahedra, and faces with four equivalent Mg(1)Mg8Si2Sn2 cuboctahedra. There is one shorter (2.92 Å) and one longer (3.16 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.08 Å) and one longer (3.21 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.22 Å. Both Mg(1)-Mg(4) bond lengths are 3.14 Å. There is one shorter (3.11 Å) and one longer (3.18 Å) Mg(1)-Sn(1) bond length. Both Mg(1)-Si(1) bond lengths are 3.01 Å. In the second Mg site, Mg(2) is bonded in a distorted linear geometry to four equivalent Mg(1) and two equivalent Sn(1) atoms. Both Mg(2)-Sn(1) bond lengths are 3.04 Å. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent Mg(1), two equivalent Sn(1), and one Si(1) atom. Both Mg(3)-Sn(1) bond lengths are 3.10 Å. The Mg(3)-Si(1) bond length is 2.90 Å. In the fourth Mg site, Mg(4) is bonded to four equivalent Mg(1) and two equivalent Si(1) atoms to form distorted MgMg4Si2 cuboctahedra that share corners with two equivalent Mg(4)Mg4Si2 cuboctahedra, edges with two equivalent Mg(4)Mg4Si2 cuboctahedra, and edges with eight equivalent Mg(1)Mg8Si2Sn2 cuboctahedra. Both Mg(4)-Si(1) bond lengths are 3.06 Å. Sn(1) is bonded in a distorted q6 geometry to two equivalent Mg(2), four equivalent Mg(1), and four equivalent Mg(3) atoms. Si(1) is bonded in a 8-coordinate geometry to two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.