MgCe2 is beta-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to three equivalent Mg(1), four equivalent Ce(2), and five equivalent Ce(1) atoms to form MgCe9Mg3 cuboctahedra that share corners with six equivalent Mg(1)Ce9Mg3 cuboctahedra, corners with six equivalent Ce(1)Ce7Mg5 cuboctahedra, corners with six equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with four equivalent Mg(1)Ce9Mg3 cuboctahedra, edges with five equivalent Ce(1)Ce7Mg5 cuboctahedra, edges with nine equivalent Ce(2)Ce8Mg4 cuboctahedra, faces with six equivalent Mg(1)Ce9Mg3 cuboctahedra, faces with six equivalent Ce(2)Ce8Mg4 cuboctahedra, and faces with eight equivalent Ce(1)Ce7Mg5 cuboctahedra. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to five equivalent Mg(1), three equivalent Ce(2), and four equivalent Ce(1) atoms to form CeCe7Mg5 cuboctahedra that share corners with six equivalent Mg(1)Ce9Mg3 cuboctahedra, corners with six equivalent Ce(1)Ce7Mg5 cuboctahedra, corners with six equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with five equivalent Mg(1)Ce9Mg3 cuboctahedra, edges with six equivalent Ce(1)Ce7Mg5 cuboctahedra, edges with seven equivalent Ce(2)Ce8Mg4 cuboctahedra, faces with five equivalent Ce(1)Ce7Mg5 cuboctahedra, faces with seven equivalent Ce(2)Ce8Mg4 cuboctahedra, and faces with eight equivalent Mg(1)Ce9Mg3 cuboctahedra. In the second Ce site, Ce(2) is bonded to four equivalent Mg(1), three equivalent Ce(1), and five equivalent Ce(2) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with six equivalent Mg(1)Ce9Mg3 cuboctahedra, corners with six equivalent Ce(1)Ce7Mg5 cuboctahedra, corners with six equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with two equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with seven equivalent Ce(1)Ce7Mg5 cuboctahedra, edges with nine equivalent Mg(1)Ce9Mg3 cuboctahedra, faces with six equivalent Mg(1)Ce9Mg3 cuboctahedra, faces with seven equivalent Ce(1)Ce7Mg5 cuboctahedra, and faces with seven equivalent Ce(2)Ce8Mg4 cuboctahedra.
MgCe2 is beta-derived structured and crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to three equivalent Mg(1), four equivalent Ce(2), and five equivalent Ce(1) atoms to form MgCe9Mg3 cuboctahedra that share corners with six equivalent Mg(1)Ce9Mg3 cuboctahedra, corners with six equivalent Ce(1)Ce7Mg5 cuboctahedra, corners with six equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with four equivalent Mg(1)Ce9Mg3 cuboctahedra, edges with five equivalent Ce(1)Ce7Mg5 cuboctahedra, edges with nine equivalent Ce(2)Ce8Mg4 cuboctahedra, faces with six equivalent Mg(1)Ce9Mg3 cuboctahedra, faces with six equivalent Ce(2)Ce8Mg4 cuboctahedra, and faces with eight equivalent Ce(1)Ce7Mg5 cuboctahedra. There is one shorter (3.12 Å) and two longer (3.23 Å) Mg(1)-Mg(1) bond lengths. There are two shorter (3.29 Å) and two longer (3.44 Å) Mg(1)-Ce(2) bond lengths. There are a spread of Mg(1)-Ce(1) bond distances ranging from 3.40-3.47 Å. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to five equivalent Mg(1), three equivalent Ce(2), and four equivalent Ce(1) atoms to form CeCe7Mg5 cuboctahedra that share corners with six equivalent Mg(1)Ce9Mg3 cuboctahedra, corners with six equivalent Ce(1)Ce7Mg5 cuboctahedra, corners with six equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with five equivalent Mg(1)Ce9Mg3 cuboctahedra, edges with six equivalent Ce(1)Ce7Mg5 cuboctahedra, edges with seven equivalent Ce(2)Ce8Mg4 cuboctahedra, faces with five equivalent Ce(1)Ce7Mg5 cuboctahedra, faces with seven equivalent Ce(2)Ce8Mg4 cuboctahedra, and faces with eight equivalent Mg(1)Ce9Mg3 cuboctahedra. There are two shorter (3.29 Å) and one longer (3.31 Å) Ce(1)-Ce(2) bond length. There are two shorter (3.21 Å) and two longer (3.23 Å) Ce(1)-Ce(1) bond lengths. In the second Ce site, Ce(2) is bonded to four equivalent Mg(1), three equivalent Ce(1), and five equivalent Ce(2) atoms to form distorted CeCe8Mg4 cuboctahedra that share corners with six equivalent Mg(1)Ce9Mg3 cuboctahedra, corners with six equivalent Ce(1)Ce7Mg5 cuboctahedra, corners with six equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with two equivalent Ce(2)Ce8Mg4 cuboctahedra, edges with seven equivalent Ce(1)Ce7Mg5 cuboctahedra, edges with nine equivalent Mg(1)Ce9Mg3 cuboctahedra, faces with six equivalent Mg(1)Ce9Mg3 cuboctahedra, faces with seven equivalent Ce(1)Ce7Mg5 cuboctahedra, and faces with seven equivalent Ce(2)Ce8Mg4 cuboctahedra. There are a spread of Ce(2)-Ce(2) bond distances ranging from 3.23-3.51 Å.