CeMg2 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded to seven equivalent Mg(1) and five equivalent Ce(1) atoms to form distorted MgCe5Mg7 cuboctahedra that share corners with six equivalent Ce(1)Ce2Mg10 cuboctahedra, corners with twelve equivalent Mg(1)Ce5Mg7 cuboctahedra, edges with four equivalent Ce(1)Ce2Mg10 cuboctahedra, edges with fourteen equivalent Mg(1)Ce5Mg7 cuboctahedra, faces with eight equivalent Ce(1)Ce2Mg10 cuboctahedra, and faces with twelve equivalent Mg(1)Ce5Mg7 cuboctahedra. Ce(1) is bonded to ten equivalent Mg(1) and two equivalent Ce(1) atoms to form CeCe2Mg10 cuboctahedra that share corners with six equivalent Ce(1)Ce2Mg10 cuboctahedra, corners with twelve equivalent Mg(1)Ce5Mg7 cuboctahedra, edges with eight equivalent Mg(1)Ce5Mg7 cuboctahedra, edges with ten equivalent Ce(1)Ce2Mg10 cuboctahedra, faces with four equivalent Ce(1)Ce2Mg10 cuboctahedra, and faces with sixteen equivalent Mg(1)Ce5Mg7 cuboctahedra.
CeMg2 crystallizes in the monoclinic C2/c space group. Mg(1) is bonded to seven equivalent Mg(1) and five equivalent Ce(1) atoms to form distorted MgCe5Mg7 cuboctahedra that share corners with six equivalent Ce(1)Ce2Mg10 cuboctahedra, corners with twelve equivalent Mg(1)Ce5Mg7 cuboctahedra, edges with four equivalent Ce(1)Ce2Mg10 cuboctahedra, edges with fourteen equivalent Mg(1)Ce5Mg7 cuboctahedra, faces with eight equivalent Ce(1)Ce2Mg10 cuboctahedra, and faces with twelve equivalent Mg(1)Ce5Mg7 cuboctahedra. There are a spread of Mg(1)-Mg(1) bond distances ranging from 3.14-3.46 Å. There are a spread of Mg(1)-Ce(1) bond distances ranging from 3.31-3.48 Å. Ce(1) is bonded to ten equivalent Mg(1) and two equivalent Ce(1) atoms to form CeCe2Mg10 cuboctahedra that share corners with six equivalent Ce(1)Ce2Mg10 cuboctahedra, corners with twelve equivalent Mg(1)Ce5Mg7 cuboctahedra, edges with eight equivalent Mg(1)Ce5Mg7 cuboctahedra, edges with ten equivalent Ce(1)Ce2Mg10 cuboctahedra, faces with four equivalent Ce(1)Ce2Mg10 cuboctahedra, and faces with sixteen equivalent Mg(1)Ce5Mg7 cuboctahedra. Both Ce(1)-Ce(1) bond lengths are 3.12 Å.