MgCd2 crystallizes in the trigonal R32 space group. Mg(1) is bonded to three equivalent Mg(1), three equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted MgMg3Cd9 cuboctahedra that share corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(1)Mg3Cd9 cuboctahedra, edges with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(1)Mg3Cd9 cuboctahedra, faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra, and faces with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to four equivalent Mg(1), two equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with eighteen Cd(1,1,1)Mg4Cd8 cuboctahedra; edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra; edges with six equivalent Cd(1)Mg4Cd8 cuboctahedra; edges with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra; faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; and faces with eight Cd(1,1)Mg4Cd8 cuboctahedra. In the second Cd site, Cd(2) is bonded to six equivalent Mg(1) and six equivalent Cd(1) atoms to form CdMg6Cd6 cuboctahedra that share corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Cd9 cuboctahedra, edges with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra, faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra. In the third Cd site, Cd(1) is bonded to four equivalent Mg(1), two equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with eighteen Cd(1,1)Mg4Cd8 cuboctahedra; edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra; edges with six equivalent Cd(1)Mg4Cd8 cuboctahedra; edges with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra; faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; and faces with eight Cd(1,1)Mg4Cd8 cuboctahedra. In the fourth Cd site, Cd(1) is bonded to four equivalent Mg(1); two equivalent Cd(2); and six Cd(1,1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with eighteen Cd(1,1,1)Mg4Cd8 cuboctahedra; edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra; edges with six equivalent Cd(1)Mg4Cd8 cuboctahedra; edges with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra; faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; and faces with eight Cd(1,1,1)Mg4Cd8 cuboctahedra.
MgCd2 crystallizes in the trigonal R32 space group. Mg(1) is bonded to three equivalent Mg(1), three equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted MgMg3Cd9 cuboctahedra that share corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Cd9 cuboctahedra, edges with six equivalent Mg(1)Mg3Cd9 cuboctahedra, edges with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra, faces with four equivalent Mg(1)Mg3Cd9 cuboctahedra, faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra, and faces with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra. All Mg(1)-Mg(1) bond lengths are 3.12 Å. All Mg(1)-Cd(2) bond lengths are 3.12 Å. There are three shorter (3.09 Å) and three longer (3.10 Å) Mg(1)-Cd(1) bond lengths. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to four equivalent Mg(1), two equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with eighteen Cd(1,1,1)Mg4Cd8 cuboctahedra; edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra; edges with six equivalent Cd(1)Mg4Cd8 cuboctahedra; edges with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra; faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; and faces with eight Cd(1,1)Mg4Cd8 cuboctahedra. Both Cd(1)-Cd(2) bond lengths are 3.10 Å. All Cd(1)-Cd(1) bond lengths are 3.12 Å. In the second Cd site, Cd(2) is bonded to six equivalent Mg(1) and six equivalent Cd(1) atoms to form CdMg6Cd6 cuboctahedra that share corners with six equivalent Cd(2)Mg6Cd6 cuboctahedra, corners with twelve equivalent Mg(1)Mg3Cd9 cuboctahedra, edges with six equivalent Cd(2)Mg6Cd6 cuboctahedra, edges with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra, faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra, and faces with twelve equivalent Cd(1)Mg4Cd8 cuboctahedra. In the third Cd site, Cd(1) is bonded to four equivalent Mg(1), two equivalent Cd(2), and six equivalent Cd(1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with eighteen Cd(1,1)Mg4Cd8 cuboctahedra; edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra; edges with six equivalent Cd(1)Mg4Cd8 cuboctahedra; edges with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra; faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; and faces with eight Cd(1,1)Mg4Cd8 cuboctahedra. There are two shorter (3.09 Å) and two longer (3.10 Å) Cd(1)-Mg(1) bond lengths. Both Cd(1)-Cd(2) bond lengths are 3.10 Å. All Cd(1)-Cd(1) bond lengths are 3.12 Å. In the fourth Cd site, Cd(1) is bonded to four equivalent Mg(1); two equivalent Cd(2); and six Cd(1,1) atoms to form distorted CdMg4Cd8 cuboctahedra that share corners with eighteen Cd(1,1,1)Mg4Cd8 cuboctahedra; edges with four equivalent Cd(2)Mg6Cd6 cuboctahedra; edges with six equivalent Cd(1)Mg4Cd8 cuboctahedra; edges with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; faces with four equivalent Cd(2)Mg6Cd6 cuboctahedra; faces with eight equivalent Mg(1)Mg3Cd9 cuboctahedra; and faces with eight Cd(1,1,1)Mg4Cd8 cuboctahedra. There are two shorter (3.09 Å) and two longer (3.10 Å) Cd(1)-Mg(1) bond lengths. Both Cd(1)-Cd(2) bond lengths are 3.10 Å. All Cd(1)-Cd(1) bond lengths are 3.12 Å.