KMg6Cr crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form KMg10Cr2 cuboctahedra that share corners with four equivalent Mg(2)K2Mg10 cuboctahedra, corners with six equivalent K(1)Mg10Cr2 cuboctahedra, corners with eight equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with two equivalent Mg(2)K2Mg10 cuboctahedra, edges with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra, faces with two equivalent K(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with four equivalent Mg(1)K2Mg8Cr2 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 to two equivalent K(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Cr(1) atoms to form distorted MgK2Mg8Cr2 cuboctahedra that share corners with four equivalent K(1)Mg10Cr2 cuboctahedra, corners with four equivalent Mg(2)K2Mg10 cuboctahedra, corners with ten equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with two equivalent K(1)Mg10Cr2 cuboctahedra, edges with two equivalent Mg(2)K2Mg10 cuboctahedra, edges with two equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent K(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, and faces with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent K(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgK2Mg10 cuboctahedra that share corners with four equivalent K(1)Mg10Cr2 cuboctahedra, corners with six equivalent Mg(2)K2Mg10 cuboctahedra, corners with eight equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with two equivalent K(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent K(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, and faces with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent K(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)K2Mg10 cuboctahedra, edges with eight equivalent Mg(1)K2Mg8Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra, and faces with six equivalent K(1)Mg10Cr2 cuboctahedra. Cr(1) is bonded in a 10-coordinate geometry to two equivalent K(1), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.
KMg6Cr crystallizes in the orthorhombic Amm2 space group. K(1) is bonded to two equivalent Mg(2), four equivalent Mg(1), four equivalent Mg(3), and two equivalent Cr(1) atoms to form KMg10Cr2 cuboctahedra that share corners with four equivalent Mg(2)K2Mg10 cuboctahedra, corners with six equivalent K(1)Mg10Cr2 cuboctahedra, corners with eight equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with two equivalent Mg(2)K2Mg10 cuboctahedra, edges with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra, faces with two equivalent K(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra, and faces with six equivalent Mg(4)Mg10Cr2 cuboctahedra. Both K(1)-Mg(2) bond lengths are 3.31 Å. There are two shorter (3.27 Å) and two longer (3.38 Å) K(1)-Mg(1) bond lengths. All K(1)-Mg(3) bond lengths are 3.34 Å. Both K(1)-Cr(1) bond lengths are 3.38 Å. There are four inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent K(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), two equivalent Mg(4), and two equivalent Cr(1) atoms to form distorted MgK2Mg8Cr2 cuboctahedra that share corners with four equivalent K(1)Mg10Cr2 cuboctahedra, corners with four equivalent Mg(2)K2Mg10 cuboctahedra, corners with ten equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with two equivalent K(1)Mg10Cr2 cuboctahedra, edges with two equivalent Mg(2)K2Mg10 cuboctahedra, edges with two equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent K(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, and faces with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra. There is one shorter (3.20 Å) and one longer (3.41 Å) Mg(1)-Mg(1) bond length. There is one shorter (3.31 Å) and one longer (3.34 Å) Mg(1)-Mg(2) bond length. Both Mg(1)-Mg(3) bond lengths are 3.25 Å. Both Mg(1)-Mg(4) bond lengths are 3.29 Å. Both Mg(1)-Cr(1) bond lengths are 3.19 Å. In the second Mg site, Mg(2) is bonded to two equivalent K(1), two equivalent Mg(4), four equivalent Mg(1), and four equivalent Mg(3) atoms to form distorted MgK2Mg10 cuboctahedra that share corners with four equivalent K(1)Mg10Cr2 cuboctahedra, corners with six equivalent Mg(2)K2Mg10 cuboctahedra, corners with eight equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with two equivalent K(1)Mg10Cr2 cuboctahedra, edges with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra, edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with two equivalent K(1)Mg10Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, and faces with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra. Both Mg(2)-Mg(4) bond lengths are 3.28 Å. All Mg(2)-Mg(3) bond lengths are 3.24 Å. In the third Mg site, Mg(3) is bonded in a 3-coordinate geometry to two equivalent K(1), two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(4), and one Cr(1) atom. There is one shorter (3.32 Å) and one longer (3.34 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)K2Mg10 cuboctahedra, edges with eight equivalent Mg(1)K2Mg8Cr2 cuboctahedra, faces with two equivalent Mg(2)K2Mg10 cuboctahedra, faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra, faces with four equivalent Mg(1)K2Mg8Cr2 cuboctahedra, and faces with six equivalent K(1)Mg10Cr2 cuboctahedra. Both Mg(4)-Cr(1) bond lengths are 3.31 Å. Cr(1) is bonded in a 10-coordinate geometry to two equivalent K(1), two equivalent Mg(3), two equivalent Mg(4), and four equivalent Mg(1) atoms.