SrMg6Cr crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form SrMg10Cr2 cuboctahedra that share corners with four equivalent Mg(2)Sr2Mg10 cuboctahedra, corners with six equivalent Sr(1)Mg10Cr2 cuboctahedra, edges with two equivalent Mg(2)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Mg10Cr2 cuboctahedra. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Cr(1) atoms. In the second Mg site, Mg(2) is bonded to two equivalent Sr(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Sr(1)Mg10Cr2 cuboctahedra, corners with six equivalent Mg(2)Sr2Mg10 cuboctahedra, edges with two equivalent Sr(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent Sr(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, and faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Cr(1) atom. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form distorted MgMg10Cr2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(2)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra, and faces with six equivalent Sr(1)Mg10Cr2 cuboctahedra. Cr(1) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.
SrMg6Cr crystallizes in the orthorhombic Amm2 space group. Sr(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form SrMg10Cr2 cuboctahedra that share corners with four equivalent Mg(2)Sr2Mg10 cuboctahedra, corners with six equivalent Sr(1)Mg10Cr2 cuboctahedra, edges with two equivalent Mg(2)Sr2Mg10 cuboctahedra, faces with two equivalent Sr(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra, and faces with six equivalent Mg(4)Mg10Cr2 cuboctahedra. Both Sr(1)-Mg(2) bond lengths are 3.34 Å. There are two shorter (3.29 Å) and two longer (3.42 Å) Sr(1)-Mg(1) bond lengths. All Sr(1)-Mg(3) bond lengths are 3.34 Å. Both Sr(1)-Cr(1) bond lengths are 3.32 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 12-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Cr(1) atoms. There is one shorter (3.19 Å) and one longer (3.50 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.25 Å) and one longer (3.46 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.18 Å. Both Mg(1)-Mg(4) bond lengths are 3.29 Å. Both Mg(1)-Cr(1) bond lengths are 3.16 Å. In the second Mg site, Mg(2) is bonded to two equivalent Sr(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgSr2Mg10 cuboctahedra that share corners with four equivalent Sr(1)Mg10Cr2 cuboctahedra, corners with six equivalent Mg(2)Sr2Mg10 cuboctahedra, edges with two equivalent Sr(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent Sr(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, and faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.27 Å. All Mg(2)-Mg(3) bond lengths are 3.20 Å. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent Sr(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Cr(1) atom. There is one shorter (3.33 Å) and one longer (3.39 Å) Mg(3)-Mg(4) bond length. The Mg(3)-Cr(1) bond length is 3.07 Å. In the fourth Mg site, Mg(4) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form distorted MgMg10Cr2 cuboctahedra that share corners with six equivalent Mg(4)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(2)Sr2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)Sr2Mg10 cuboctahedra, and faces with six equivalent Sr(1)Mg10Cr2 cuboctahedra. Both Mg(4)-Cr(1) bond lengths are 3.35 Å. Cr(1) is bonded in a 10-coordinate geometry to two equivalent Sr(1), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.