CeMg2 is beta-derived structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent Mg(1), five equivalent Mg(2), and three equivalent Ce(1) atoms to form MgCe3Mg9 cuboctahedra that share corners with six equivalent Mg(1)Ce3Mg9 cuboctahedra, corners with six equivalent Mg(2)Ce4Mg8 cuboctahedra, corners with six equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with five equivalent Mg(2)Ce4Mg8 cuboctahedra, edges with six equivalent Mg(1)Ce3Mg9 cuboctahedra, edges with seven equivalent Ce(1)Ce5Mg7 cuboctahedra, faces with five equivalent Mg(1)Ce3Mg9 cuboctahedra, faces with seven equivalent Ce(1)Ce5Mg7 cuboctahedra, and faces with eight equivalent Mg(2)Ce4Mg8 cuboctahedra. In the second Mg site, Mg(2) is bonded to three equivalent Mg(2), five equivalent Mg(1), and four equivalent Ce(1) atoms to form MgCe4Mg8 cuboctahedra that share corners with six equivalent Mg(1)Ce3Mg9 cuboctahedra, corners with six equivalent Mg(2)Ce4Mg8 cuboctahedra, corners with six equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with four equivalent Mg(2)Ce4Mg8 cuboctahedra, edges with five equivalent Mg(1)Ce3Mg9 cuboctahedra, edges with nine equivalent Ce(1)Ce5Mg7 cuboctahedra, faces with six equivalent Mg(2)Ce4Mg8 cuboctahedra, faces with six equivalent Ce(1)Ce5Mg7 cuboctahedra, and faces with eight equivalent Mg(1)Ce3Mg9 cuboctahedra. Ce(1) is bonded to three equivalent Mg(1), four equivalent Mg(2), and five equivalent Ce(1) atoms to form CeCe5Mg7 cuboctahedra that share corners with six equivalent Mg(1)Ce3Mg9 cuboctahedra, corners with six equivalent Mg(2)Ce4Mg8 cuboctahedra, corners with six equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with two equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with seven equivalent Mg(1)Ce3Mg9 cuboctahedra, edges with nine equivalent Mg(2)Ce4Mg8 cuboctahedra, faces with six equivalent Mg(2)Ce4Mg8 cuboctahedra, faces with seven equivalent Mg(1)Ce3Mg9 cuboctahedra, and faces with seven equivalent Ce(1)Ce5Mg7 cuboctahedra.
CeMg2 is beta-derived structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent Mg(1), five equivalent Mg(2), and three equivalent Ce(1) atoms to form MgCe3Mg9 cuboctahedra that share corners with six equivalent Mg(1)Ce3Mg9 cuboctahedra, corners with six equivalent Mg(2)Ce4Mg8 cuboctahedra, corners with six equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with five equivalent Mg(2)Ce4Mg8 cuboctahedra, edges with six equivalent Mg(1)Ce3Mg9 cuboctahedra, edges with seven equivalent Ce(1)Ce5Mg7 cuboctahedra, faces with five equivalent Mg(1)Ce3Mg9 cuboctahedra, faces with seven equivalent Ce(1)Ce5Mg7 cuboctahedra, and faces with eight equivalent Mg(2)Ce4Mg8 cuboctahedra. There are two shorter (3.17 Å) and two longer (3.28 Å) Mg(1)-Mg(1) bond lengths. There are a spread of Mg(1)-Mg(2) bond distances ranging from 3.10-3.19 Å. There are two shorter (3.43 Å) and one longer (3.51 Å) Mg(1)-Ce(1) bond length. In the second Mg site, Mg(2) is bonded to three equivalent Mg(2), five equivalent Mg(1), and four equivalent Ce(1) atoms to form MgCe4Mg8 cuboctahedra that share corners with six equivalent Mg(1)Ce3Mg9 cuboctahedra, corners with six equivalent Mg(2)Ce4Mg8 cuboctahedra, corners with six equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with four equivalent Mg(2)Ce4Mg8 cuboctahedra, edges with five equivalent Mg(1)Ce3Mg9 cuboctahedra, edges with nine equivalent Ce(1)Ce5Mg7 cuboctahedra, faces with six equivalent Mg(2)Ce4Mg8 cuboctahedra, faces with six equivalent Ce(1)Ce5Mg7 cuboctahedra, and faces with eight equivalent Mg(1)Ce3Mg9 cuboctahedra. There are two shorter (3.28 Å) and one longer (3.30 Å) Mg(2)-Mg(2) bond length. There are two shorter (3.48 Å) and two longer (3.49 Å) Mg(2)-Ce(1) bond lengths. Ce(1) is bonded to three equivalent Mg(1), four equivalent Mg(2), and five equivalent Ce(1) atoms to form CeCe5Mg7 cuboctahedra that share corners with six equivalent Mg(1)Ce3Mg9 cuboctahedra, corners with six equivalent Mg(2)Ce4Mg8 cuboctahedra, corners with six equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with two equivalent Ce(1)Ce5Mg7 cuboctahedra, edges with seven equivalent Mg(1)Ce3Mg9 cuboctahedra, edges with nine equivalent Mg(2)Ce4Mg8 cuboctahedra, faces with six equivalent Mg(2)Ce4Mg8 cuboctahedra, faces with seven equivalent Mg(1)Ce3Mg9 cuboctahedra, and faces with seven equivalent Ce(1)Ce5Mg7 cuboctahedra. There are a spread of Ce(1)-Ce(1) bond distances ranging from 2.82-3.49 Å.