PmSi3 crystallizes in the hexagonal P6_3/mmc space group. Pm(1) is bonded to twelve equivalent Si(1) atoms to form a mixture of distorted face and corner-sharing PmSi12 cuboctahedra. Si(1) is bonded in a 10-coordinate geometry to four equivalent Pm(1) and six equivalent Si(1) atoms.
PmSi3 crystallizes in the hexagonal P6_3/mmc space group. Pm(1) is bonded to twelve equivalent Si(1) atoms to form a mixture of distorted face and corner-sharing PmSi12 cuboctahedra. There are six shorter (3.08 Å) and six longer (3.14 Å) Pm(1)-Si(1) bond lengths. Si(1) is bonded in a 10-coordinate geometry to four equivalent Pm(1) and six equivalent Si(1) atoms. There are two shorter (2.47 Å) and four longer (2.73 Å) Si(1)-Si(1) bond lengths.