SrMg6Sn crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form SrMg10Sn2 cuboctahedra that share corners with four equivalent Sn(1)Sr2Mg10 cuboctahedra, corners with six equivalent Sr(1)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sn(1)Sr2Mg10 cuboctahedra, edges with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, faces with two equivalent Sr(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Sr2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Sn(1) atoms to form MgSr2Mg8Sn2 cuboctahedra that share corners with four equivalent Sr(1)Mg10Sn2 cuboctahedra, corners with four equivalent Sn(1)Sr2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sr(1)Mg10Sn2 cuboctahedra, edges with two equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sn(1)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Sr2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Mg(4), two equivalent Mg(1), and two equivalent Sn(1) atoms. In the third Mg site, Mg(3) is bonded in a distorted water-like geometry to two equivalent Mg(4), four equivalent Mg(1), and two equivalent Sn(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(3), and four equivalent Mg(1) atoms. Sn(1) is bonded to two equivalent Sr(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted SnSr2Mg10 cuboctahedra that share corners with four equivalent Sr(1)Mg10Sn2 cuboctahedra, corners with six equivalent Sn(1)Sr2Mg10 cuboctahedra, corners with eight equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sr(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, faces with two equivalent Sr(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Sr2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra.
SrMg6Sn crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(4), four equivalent Mg(1), four equivalent Mg(2), and two equivalent Sn(1) atoms to form SrMg10Sn2 cuboctahedra that share corners with four equivalent Sn(1)Sr2Mg10 cuboctahedra, corners with six equivalent Sr(1)Mg10Sn2 cuboctahedra, corners with eight equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sn(1)Sr2Mg10 cuboctahedra, edges with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, faces with two equivalent Sr(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Sr2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra. Both Sr(1)-Mg(4) bond lengths are 3.35 Å. There are two shorter (3.42 Å) and two longer (3.47 Å) Sr(1)-Mg(1) bond lengths. All Sr(1)-Mg(2) bond lengths are 3.33 Å. Both Sr(1)-Sn(1) bond lengths are 3.28 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Sn(1) atoms to form MgSr2Mg8Sn2 cuboctahedra that share corners with four equivalent Sr(1)Mg10Sn2 cuboctahedra, corners with four equivalent Sn(1)Sr2Mg10 cuboctahedra, corners with ten equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sr(1)Mg10Sn2 cuboctahedra, edges with two equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sn(1)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Sr2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra. There is one shorter (3.26 Å) and one longer (3.30 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Mg(2) bond lengths are 3.25 Å. Both Mg(1)-Mg(3) bond lengths are 3.27 Å. Both Mg(1)-Mg(4) bond lengths are 3.23 Å. There is one shorter (3.38 Å) and one longer (3.51 Å) Mg(1)-Sn(1) bond length. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Mg(4), two equivalent Mg(1), and two equivalent Sn(1) atoms. The Mg(2)-Mg(4) bond length is 3.24 Å. Both Mg(2)-Sn(1) bond lengths are 3.25 Å. In the third Mg site, Mg(3) is bonded in a distorted water-like geometry to two equivalent Mg(4), four equivalent Mg(1), and two equivalent Sn(1) atoms. Both Mg(3)-Mg(4) bond lengths are 3.28 Å. Both Mg(3)-Sn(1) bond lengths are 3.35 Å. In the fourth Mg site, Mg(4) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent Mg(2), two equivalent Mg(3), and four equivalent Mg(1) atoms. Sn(1) is bonded to two equivalent Sr(1), two equivalent Mg(3), four equivalent Mg(1), and four equivalent Mg(2) atoms to form distorted SnSr2Mg10 cuboctahedra that share corners with four equivalent Sr(1)Mg10Sn2 cuboctahedra, corners with six equivalent Sn(1)Sr2Mg10 cuboctahedra, corners with eight equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, edges with two equivalent Sr(1)Mg10Sn2 cuboctahedra, edges with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra, faces with two equivalent Sr(1)Mg10Sn2 cuboctahedra, faces with two equivalent Sn(1)Sr2Mg10 cuboctahedra, and faces with four equivalent Mg(1)Sr2Mg8Sn2 cuboctahedra.