PmY3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Pm(1) is bonded to four equivalent Y(2) and eight equivalent Y(1) atoms to form PmY12 cuboctahedra that share corners with four equivalent Pm(1)Y12 cuboctahedra, corners with eight equivalent Y(2)Pm4Y8 cuboctahedra, edges with eight equivalent Pm(1)Y12 cuboctahedra, edges with sixteen equivalent Y(1)Pm4Y8 cuboctahedra, faces with four equivalent Pm(1)Y12 cuboctahedra, faces with six equivalent Y(2)Pm4Y8 cuboctahedra, and faces with eight equivalent Y(1)Pm4Y8 cuboctahedra. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Pm(1), four equivalent Y(1), and four equivalent Y(2) atoms to form YPm4Y8 cuboctahedra that share corners with twelve equivalent Y(1)Pm4Y8 cuboctahedra, edges with eight equivalent Pm(1)Y12 cuboctahedra, edges with eight equivalent Y(1)Pm4Y8 cuboctahedra, edges with eight equivalent Y(2)Pm4Y8 cuboctahedra, faces with four equivalent Pm(1)Y12 cuboctahedra, faces with four equivalent Y(2)Pm4Y8 cuboctahedra, and faces with ten equivalent Y(1)Pm4Y8 cuboctahedra. In the second Y site, Y(2) is bonded to four equivalent Pm(1) and eight equivalent Y(1) atoms to form YPm4Y8 cuboctahedra that share corners with four equivalent Y(2)Pm4Y8 cuboctahedra, corners with eight equivalent Pm(1)Y12 cuboctahedra, edges with eight equivalent Y(2)Pm4Y8 cuboctahedra, edges with sixteen equivalent Y(1)Pm4Y8 cuboctahedra, faces with four equivalent Y(2)Pm4Y8 cuboctahedra, faces with six equivalent Pm(1)Y12 cuboctahedra, and faces with eight equivalent Y(1)Pm4Y8 cuboctahedra.
PmY3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. Pm(1) is bonded to four equivalent Y(2) and eight equivalent Y(1) atoms to form PmY12 cuboctahedra that share corners with four equivalent Pm(1)Y12 cuboctahedra, corners with eight equivalent Y(2)Pm4Y8 cuboctahedra, edges with eight equivalent Pm(1)Y12 cuboctahedra, edges with sixteen equivalent Y(1)Pm4Y8 cuboctahedra, faces with four equivalent Pm(1)Y12 cuboctahedra, faces with six equivalent Y(2)Pm4Y8 cuboctahedra, and faces with eight equivalent Y(1)Pm4Y8 cuboctahedra. All Pm(1)-Y(2) bond lengths are 3.62 Å. All Pm(1)-Y(1) bond lengths are 3.62 Å. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to four equivalent Pm(1), four equivalent Y(1), and four equivalent Y(2) atoms to form YPm4Y8 cuboctahedra that share corners with twelve equivalent Y(1)Pm4Y8 cuboctahedra, edges with eight equivalent Pm(1)Y12 cuboctahedra, edges with eight equivalent Y(1)Pm4Y8 cuboctahedra, edges with eight equivalent Y(2)Pm4Y8 cuboctahedra, faces with four equivalent Pm(1)Y12 cuboctahedra, faces with four equivalent Y(2)Pm4Y8 cuboctahedra, and faces with ten equivalent Y(1)Pm4Y8 cuboctahedra. All Y(1)-Y(1) bond lengths are 3.62 Å. All Y(1)-Y(2) bond lengths are 3.62 Å. In the second Y site, Y(2) is bonded to four equivalent Pm(1) and eight equivalent Y(1) atoms to form YPm4Y8 cuboctahedra that share corners with four equivalent Y(2)Pm4Y8 cuboctahedra, corners with eight equivalent Pm(1)Y12 cuboctahedra, edges with eight equivalent Y(2)Pm4Y8 cuboctahedra, edges with sixteen equivalent Y(1)Pm4Y8 cuboctahedra, faces with four equivalent Y(2)Pm4Y8 cuboctahedra, faces with six equivalent Pm(1)Y12 cuboctahedra, and faces with eight equivalent Y(1)Pm4Y8 cuboctahedra.