Ba3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded to eight equivalent Ba(1) and four equivalent Pm(1) atoms to form distorted BaBa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Ba12 cuboctahedra, corners with fourteen equivalent Ba(1)Ba8Pm4 cuboctahedra, edges with six equivalent Pm(1)Ba12 cuboctahedra, edges with twelve equivalent Ba(1)Ba8Pm4 cuboctahedra, faces with four equivalent Pm(1)Ba12 cuboctahedra, and faces with sixteen equivalent Ba(1)Ba8Pm4 cuboctahedra. Pm(1) is bonded to twelve equivalent Ba(1) atoms to form PmBa12 cuboctahedra that share corners with six equivalent Pm(1)Ba12 cuboctahedra, corners with twelve equivalent Ba(1)Ba8Pm4 cuboctahedra, edges with eighteen equivalent Ba(1)Ba8Pm4 cuboctahedra, faces with eight equivalent Pm(1)Ba12 cuboctahedra, and faces with twelve equivalent Ba(1)Ba8Pm4 cuboctahedra.
Ba3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded to eight equivalent Ba(1) and four equivalent Pm(1) atoms to form distorted BaBa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Ba12 cuboctahedra, corners with fourteen equivalent Ba(1)Ba8Pm4 cuboctahedra, edges with six equivalent Pm(1)Ba12 cuboctahedra, edges with twelve equivalent Ba(1)Ba8Pm4 cuboctahedra, faces with four equivalent Pm(1)Ba12 cuboctahedra, and faces with sixteen equivalent Ba(1)Ba8Pm4 cuboctahedra. There are a spread of Ba(1)-Ba(1) bond distances ranging from 4.11-4.41 Å. There are two shorter (4.13 Å) and two longer (4.26 Å) Ba(1)-Pm(1) bond lengths. Pm(1) is bonded to twelve equivalent Ba(1) atoms to form PmBa12 cuboctahedra that share corners with six equivalent Pm(1)Ba12 cuboctahedra, corners with twelve equivalent Ba(1)Ba8Pm4 cuboctahedra, edges with eighteen equivalent Ba(1)Ba8Pm4 cuboctahedra, faces with eight equivalent Pm(1)Ba12 cuboctahedra, and faces with twelve equivalent Ba(1)Ba8Pm4 cuboctahedra.