Mg6Sn2Si crystallizes in the orthorhombic Immm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Sn(1) and two equivalent Si(1) atoms to form MgSi2Sn2 tetrahedra that share corners with four equivalent Mg(1)Si2Sn2 tetrahedra, corners with twelve equivalent Mg(2)SiSn3 tetrahedra, edges with two equivalent Mg(1)Si2Sn2 tetrahedra, and edges with four equivalent Mg(2)SiSn3 tetrahedra. In the second Mg site, Mg(2) is bonded to three equivalent Sn(1) and one Si(1) atom to form MgSiSn3 tetrahedra that share corners with six equivalent Mg(1)Si2Sn2 tetrahedra, corners with ten equivalent Mg(2)SiSn3 tetrahedra, edges with two equivalent Mg(1)Si2Sn2 tetrahedra, and edges with four equivalent Mg(2)SiSn3 tetrahedra. Sn(1) is bonded in a body-centered cubic geometry to two equivalent Mg(1) and six equivalent Mg(2) atoms. Si(1) is bonded in a body-centered cubic geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms.
Mg6Sn2Si crystallizes in the orthorhombic Immm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Sn(1) and two equivalent Si(1) atoms to form MgSi2Sn2 tetrahedra that share corners with four equivalent Mg(1)Si2Sn2 tetrahedra, corners with twelve equivalent Mg(2)SiSn3 tetrahedra, edges with two equivalent Mg(1)Si2Sn2 tetrahedra, and edges with four equivalent Mg(2)SiSn3 tetrahedra. Both Mg(1)-Sn(1) bond lengths are 2.93 Å. Both Mg(1)-Si(1) bond lengths are 2.84 Å. In the second Mg site, Mg(2) is bonded to three equivalent Sn(1) and one Si(1) atom to form MgSiSn3 tetrahedra that share corners with six equivalent Mg(1)Si2Sn2 tetrahedra, corners with ten equivalent Mg(2)SiSn3 tetrahedra, edges with two equivalent Mg(1)Si2Sn2 tetrahedra, and edges with four equivalent Mg(2)SiSn3 tetrahedra. There are two shorter (2.92 Å) and one longer (2.93 Å) Mg(2)-Sn(1) bond length. The Mg(2)-Si(1) bond length is 2.78 Å. Sn(1) is bonded in a body-centered cubic geometry to two equivalent Mg(1) and six equivalent Mg(2) atoms. Si(1) is bonded in a body-centered cubic geometry to four equivalent Mg(1) and four equivalent Mg(2) atoms.