Pm3Au crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pm is bonded in a distorted see-saw-like geometry to four equivalent Au atoms. There are two shorter (3.28 Å) and two longer (3.50 Å) Pm–Au bond lengths. Au is bonded to twelve equivalent Pm atoms to form a mixture of face and corner-sharing AuPm12 cuboctahedra.