Na3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Pm(1) atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Na12 cuboctahedra; corners with fourteen equivalent Na(1)Na8Pm4 cuboctahedra; edges with six equivalent Pm(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Pm4 cuboctahedra; faces with four equivalent Pm(1)Na12 cuboctahedra; and faces with sixteen Na(1,1,1)Na8Pm4 cuboctahedra. In the second Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Pm(1) atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Na12 cuboctahedra; corners with fourteen Na(1,1,1)Na8Pm4 cuboctahedra; edges with six equivalent Pm(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Pm4 cuboctahedra; faces with four equivalent Pm(1)Na12 cuboctahedra; and faces with sixteen Na(1,1,1)Na8Pm4 cuboctahedra. In the third Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Pm(1) atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Na12 cuboctahedra; corners with fourteen Na(1,1,1)Na8Pm4 cuboctahedra; edges with six equivalent Pm(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Pm4 cuboctahedra; faces with four equivalent Pm(1)Na12 cuboctahedra; and faces with sixteen Na(1,1,1)Na8Pm4 cuboctahedra. Pm(1) is bonded to twelve Na(1,1,1) atoms to form PmNa12 cuboctahedra that share corners with six equivalent Pm(1)Na12 cuboctahedra; corners with twelve equivalent Na(1)Na8Pm4 cuboctahedra; edges with eighteen Na(1,1,1)Na8Pm4 cuboctahedra; faces with eight equivalent Pm(1)Na12 cuboctahedra; and faces with twelve Na(1,1,1)Na8Pm4 cuboctahedra.
Na3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Pm(1) atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Na12 cuboctahedra; corners with fourteen equivalent Na(1)Na8Pm4 cuboctahedra; edges with six equivalent Pm(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Pm4 cuboctahedra; faces with four equivalent Pm(1)Na12 cuboctahedra; and faces with sixteen Na(1,1,1)Na8Pm4 cuboctahedra. There are a spread of Na(1)-Na(1,1) bond distances ranging from 3.57-3.81 Å. There are two shorter (3.64 Å) and two longer (3.72 Å) Na(1)-Pm(1) bond lengths. In the second Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Pm(1) atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Na12 cuboctahedra; corners with fourteen Na(1,1,1)Na8Pm4 cuboctahedra; edges with six equivalent Pm(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Pm4 cuboctahedra; faces with four equivalent Pm(1)Na12 cuboctahedra; and faces with sixteen Na(1,1,1)Na8Pm4 cuboctahedra. There are a spread of Na(1)-Na(1,1) bond distances ranging from 3.57-3.81 Å. There are two shorter (3.64 Å) and two longer (3.72 Å) Na(1)-Pm(1) bond lengths. In the third Na site, Na(1) is bonded to eight Na(1,1) and four equivalent Pm(1) atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent Pm(1)Na12 cuboctahedra; corners with fourteen Na(1,1,1)Na8Pm4 cuboctahedra; edges with six equivalent Pm(1)Na12 cuboctahedra; edges with twelve Na(1,1)Na8Pm4 cuboctahedra; faces with four equivalent Pm(1)Na12 cuboctahedra; and faces with sixteen Na(1,1,1)Na8Pm4 cuboctahedra. There are two shorter (3.64 Å) and two longer (3.72 Å) Na(1)-Pm(1) bond lengths. Pm(1) is bonded to twelve Na(1,1,1) atoms to form PmNa12 cuboctahedra that share corners with six equivalent Pm(1)Na12 cuboctahedra; corners with twelve equivalent Na(1)Na8Pm4 cuboctahedra; edges with eighteen Na(1,1,1)Na8Pm4 cuboctahedra; faces with eight equivalent Pm(1)Na12 cuboctahedra; and faces with twelve Na(1,1,1)Na8Pm4 cuboctahedra.