MgPa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to four equivalent Pa(1) and eight equivalent Pa(2) atoms to form MgPa12 cuboctahedra that share corners with four equivalent Mg(1)Pa12 cuboctahedra, corners with eight equivalent Pa(1)Mg4Pa8 cuboctahedra, edges with eight equivalent Mg(1)Pa12 cuboctahedra, edges with sixteen equivalent Pa(2)Mg4Pa8 cuboctahedra, faces with four equivalent Mg(1)Pa12 cuboctahedra, faces with six equivalent Pa(1)Mg4Pa8 cuboctahedra, and faces with eight equivalent Pa(2)Mg4Pa8 cuboctahedra. There are two inequivalent Pa sites. In the first Pa site, Pa(1) is bonded to four equivalent Mg(1) and eight equivalent Pa(2) atoms to form PaMg4Pa8 cuboctahedra that share corners with four equivalent Pa(1)Mg4Pa8 cuboctahedra, corners with eight equivalent Mg(1)Pa12 cuboctahedra, edges with eight equivalent Pa(1)Mg4Pa8 cuboctahedra, edges with sixteen equivalent Pa(2)Mg4Pa8 cuboctahedra, faces with four equivalent Pa(1)Mg4Pa8 cuboctahedra, faces with six equivalent Mg(1)Pa12 cuboctahedra, and faces with eight equivalent Pa(2)Mg4Pa8 cuboctahedra. In the second Pa site, Pa(2) is bonded to four equivalent Mg(1), four equivalent Pa(1), and four equivalent Pa(2) atoms to form PaMg4Pa8 cuboctahedra that share corners with twelve equivalent Pa(2)Mg4Pa8 cuboctahedra, edges with eight equivalent Mg(1)Pa12 cuboctahedra, edges with eight equivalent Pa(1)Mg4Pa8 cuboctahedra, edges with eight equivalent Pa(2)Mg4Pa8 cuboctahedra, faces with four equivalent Mg(1)Pa12 cuboctahedra, faces with four equivalent Pa(1)Mg4Pa8 cuboctahedra, and faces with ten equivalent Pa(2)Mg4Pa8 cuboctahedra.
MgPa3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. Mg(1) is bonded to four equivalent Pa(1) and eight equivalent Pa(2) atoms to form MgPa12 cuboctahedra that share corners with four equivalent Mg(1)Pa12 cuboctahedra, corners with eight equivalent Pa(1)Mg4Pa8 cuboctahedra, edges with eight equivalent Mg(1)Pa12 cuboctahedra, edges with sixteen equivalent Pa(2)Mg4Pa8 cuboctahedra, faces with four equivalent Mg(1)Pa12 cuboctahedra, faces with six equivalent Pa(1)Mg4Pa8 cuboctahedra, and faces with eight equivalent Pa(2)Mg4Pa8 cuboctahedra. All Mg(1)-Pa(1) bond lengths are 3.24 Å. All Mg(1)-Pa(2) bond lengths are 3.24 Å. There are two inequivalent Pa sites. In the first Pa site, Pa(1) is bonded to four equivalent Mg(1) and eight equivalent Pa(2) atoms to form PaMg4Pa8 cuboctahedra that share corners with four equivalent Pa(1)Mg4Pa8 cuboctahedra, corners with eight equivalent Mg(1)Pa12 cuboctahedra, edges with eight equivalent Pa(1)Mg4Pa8 cuboctahedra, edges with sixteen equivalent Pa(2)Mg4Pa8 cuboctahedra, faces with four equivalent Pa(1)Mg4Pa8 cuboctahedra, faces with six equivalent Mg(1)Pa12 cuboctahedra, and faces with eight equivalent Pa(2)Mg4Pa8 cuboctahedra. All Pa(1)-Pa(2) bond lengths are 3.24 Å. In the second Pa site, Pa(2) is bonded to four equivalent Mg(1), four equivalent Pa(1), and four equivalent Pa(2) atoms to form PaMg4Pa8 cuboctahedra that share corners with twelve equivalent Pa(2)Mg4Pa8 cuboctahedra, edges with eight equivalent Mg(1)Pa12 cuboctahedra, edges with eight equivalent Pa(1)Mg4Pa8 cuboctahedra, edges with eight equivalent Pa(2)Mg4Pa8 cuboctahedra, faces with four equivalent Mg(1)Pa12 cuboctahedra, faces with four equivalent Pa(1)Mg4Pa8 cuboctahedra, and faces with ten equivalent Pa(2)Mg4Pa8 cuboctahedra. All Pa(2)-Pa(2) bond lengths are 3.24 Å.