CaMg6Cr crystallizes in the orthorhombic Amm2 space group. Ca(1) is bonded to two equivalent Mg(3); four Mg(1,1,1); four equivalent Mg(2); and two equivalent Cr(1) atoms to form CaMg10Cr2 cuboctahedra that share corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with six equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Mg(4)Mg10Cr2 cuboctahedra. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with ten Mg(1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with two equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra. In the second Mg site, Mg(1) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with ten Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with two equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra. In the third Mg site, Mg(2) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with ten Mg(2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra. In the fourth Mg site, Mg(3) is bonded to two equivalent Ca(1); two equivalent Mg(4); four Mg(1,1); and four Mg(2,2,2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with six equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; faces with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Cr(1)Ca2Mg10 cuboctahedra. In the fifth Mg site, Mg(4) is bonded to two equivalent Mg(3); four Mg(1,1); four Mg(2,2,2); and two equivalent Cr(1) atoms to form distorted MgMg10Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with six equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; faces with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Ca(1)Mg10Cr2 cuboctahedra. In the sixth Mg site, Mg(1) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with ten Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with two equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(2,2)Ca2Mg8Cr2 cuboctahedra. In the seventh Mg site, Mg(2) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with ten Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(2,2)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra. In the eighth Mg site, Mg(2) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with ten Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(2,2)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(1,1)Ca2Mg8Cr2 cuboctahedra. Cr(1) is bonded to two equivalent Ca(1); two equivalent Mg(4); four Mg(1,1,1); and four equivalent Mg(2) atoms to form CrCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with six equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Mg(3)Ca2Mg10 cuboctahedra.
CaMg6Cr crystallizes in the orthorhombic Amm2 space group. Ca(1) is bonded to two equivalent Mg(3); four Mg(1,1,1); four equivalent Mg(2); and two equivalent Cr(1) atoms to form CaMg10Cr2 cuboctahedra that share corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with six equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Mg(4)Mg10Cr2 cuboctahedra. Both Ca(1)-Mg(3) bond lengths are 3.24 Å. There are two shorter (3.25 Å) and two longer (3.27 Å) Ca(1)-Mg(1,1,1) bond lengths. All Ca(1)-Mg(2) bond lengths are 3.25 Å. Both Ca(1)-Cr(1) bond lengths are 3.25 Å. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with ten Mg(1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with two equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra. There is one shorter (3.21 Å) and one longer (3.30 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Mg(2) bond lengths are 3.20 Å. Both Mg(1)-Mg(3) bond lengths are 3.18 Å. Both Mg(1)-Mg(4) bond lengths are 3.24 Å. There is one shorter (3.22 Å) and one longer (3.30 Å) Mg(1)-Cr(1) bond length. In the second Mg site, Mg(1) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with ten Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with two equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra. Both Mg(1)-Mg(2) bond lengths are 3.20 Å. Both Mg(1)-Mg(3) bond lengths are 3.18 Å. Both Mg(1)-Mg(4) bond lengths are 3.24 Å. There is one shorter (3.22 Å) and one longer (3.30 Å) Mg(1)-Cr(1) bond length. In the third Mg site, Mg(2) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with ten Mg(2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra. Both Mg(2)-Mg(1) bond lengths are 3.20 Å. There is one shorter (3.08 Å) and one longer (3.43 Å) Mg(2)-Mg(2) bond length. There is one shorter (3.18 Å) and one longer (3.34 Å) Mg(2)-Mg(3) bond length. There is one shorter (3.17 Å) and one longer (3.35 Å) Mg(2)-Mg(4) bond length. Both Mg(2)-Cr(1) bond lengths are 3.16 Å. In the fourth Mg site, Mg(3) is bonded to two equivalent Ca(1); two equivalent Mg(4); four Mg(1,1); and four Mg(2,2,2) atoms to form distorted MgCa2Mg10 cuboctahedra that share corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with six equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; faces with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Cr(1)Ca2Mg10 cuboctahedra. Both Mg(3)-Mg(4) bond lengths are 3.26 Å. Both Mg(3)-Mg(2,2) bond lengths are 3.18 Å. In the fifth Mg site, Mg(4) is bonded to two equivalent Mg(3); four Mg(1,1); four Mg(2,2,2); and two equivalent Cr(1) atoms to form distorted MgMg10Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with six equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; faces with four Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Ca(1)Mg10Cr2 cuboctahedra. Both Mg(4)-Mg(2,2) bond lengths are 3.35 Å. Both Mg(4)-Cr(1) bond lengths are 3.18 Å. In the sixth Mg site, Mg(1) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with four equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with ten Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with two equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Cr(1)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(2,2)Ca2Mg8Cr2 cuboctahedra. There is one shorter (3.21 Å) and one longer (3.30 Å) Mg(1)-Mg(1) bond length. Both Mg(1)-Mg(2) bond lengths are 3.20 Å. Both Mg(1)-Mg(3) bond lengths are 3.18 Å. Both Mg(1)-Mg(4) bond lengths are 3.24 Å. There is one shorter (3.22 Å) and one longer (3.30 Å) Mg(1)-Cr(1) bond length. In the seventh Mg site, Mg(2) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with ten Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(2,2)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra. Both Mg(2)-Ca(1) bond lengths are 3.25 Å. There is one shorter (3.08 Å) and one longer (3.43 Å) Mg(2)-Mg(2) bond length. Both Mg(2)-Cr(1) bond lengths are 3.16 Å. In the eighth Mg site, Mg(2) is bonded to two equivalent Ca(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 MgCa2Mg8Cr2 cuboctahedra that share corners with four equivalent Mg(3)Ca2Mg10 cuboctahedra; corners with four equivalent Mg(4)Mg10Cr2 cuboctahedra; corners with ten Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(3)Ca2Mg10 cuboctahedra; edges with two equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with four equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four equivalent Mg(1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(3)Ca2Mg10 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(2,2)Ca2Mg8Cr2 cuboctahedra; and faces with eight Mg(1,1)Ca2Mg8Cr2 cuboctahedra. Both Mg(2)-Ca(1) bond lengths are 3.25 Å. Both Mg(2)-Cr(1) bond lengths are 3.16 Å. Cr(1) is bonded to two equivalent Ca(1); two equivalent Mg(4); four Mg(1,1,1); and four equivalent Mg(2) atoms to form CrCa2Mg10 cuboctahedra that share corners with four equivalent Ca(1)Mg10Cr2 cuboctahedra; corners with six equivalent Cr(1)Ca2Mg10 cuboctahedra; corners with eight Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with two equivalent Ca(1)Mg10Cr2 cuboctahedra; edges with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; edges with four equivalent Mg(4)Mg10Cr2 cuboctahedra; edges with eight Mg(2,2,2)Ca2Mg8Cr2 cuboctahedra; faces with two equivalent Ca(1)Mg10Cr2 cuboctahedra; faces with two equivalent Mg(4)Mg10Cr2 cuboctahedra; faces with two equivalent Cr(1)Ca2Mg10 cuboctahedra; faces with four Mg(1,1,1)Ca2Mg8Cr2 cuboctahedra; faces with four equivalent Mg(2)Ca2Mg8Cr2 cuboctahedra; and faces with six equivalent Mg(3)Ca2Mg10 cuboctahedra.