Pm is alpha La structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to six equivalent Pm(1) and six equivalent Pm(2) atoms to form a mixture of face, corner, and edge-sharing PmPm12 cuboctahedra. In the second Pm site, Pm(2) is bonded to six equivalent Pm(1) and six equivalent Pm(2) atoms to form a mixture of face, corner, and edge-sharing PmPm12 cuboctahedra.
Pm is alpha La structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Pm sites. In the first Pm site, Pm(1) is bonded to six equivalent Pm(1) and six equivalent Pm(2) atoms to form a mixture of face, corner, and edge-sharing PmPm12 cuboctahedra. All Pm(1)-Pm(1) bond lengths are 3.68 Å. All Pm(1)-Pm(2) bond lengths are 3.63 Å. In the second Pm site, Pm(2) is bonded to six equivalent Pm(1) and six equivalent Pm(2) atoms to form a mixture of face, corner, and edge-sharing PmPm12 cuboctahedra. All Pm(2)-Pm(2) bond lengths are 3.68 Å.