Materials Data on Na3Pm by Materials Project
Na3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded to eight Na and four equivalent Pm atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent PmNa12 cuboctahedra, corners with fourteen equivalent NaNa8Pm4 cuboctahedra, edges with six equivalent PmNa12 cuboctahedra, edges with twelve NaNa8Pm4 cuboctahedra, faces with four equivalent PmNa12 cuboctahedra, and faces with sixteen NaNa8Pm4 cuboctahedra. There are a spread of Na–Na bond distances ranging from 3.57–3.81 Å. There are two shorter (3.64 Å) and two longer (3.72 Å) Na–Pm bond lengths. In the second Na site, Na is bonded to eight Na and four equivalent Pm atoms to form distorted NaNa8Pm4 cuboctahedra that share corners with four equivalent PmNa12 cuboctahedra, corners with fourteen NaNa8Pm4 cuboctahedra, edges with six equivalent PmNa12 cuboctahedra, edges with twelve NaNa8Pm4 cuboctahedra, faces with four equivalent PmNa12 cuboctahedra, and faces with sixteen NaNa8Pm4 cuboctahedra. There are one shorter (3.62 Å) and one longer (3.81 Å) Na–Na bond lengths. There are two shorter (3.64 Å) and two longer (3.72 Å) Na–Pm bond lengths. Pm is bonded to twelve Na atoms to form PmNa12 cuboctahedra that share corners with six equivalent PmNa12 cuboctahedra, corners with twelve equivalent NaNa8Pm4 cuboctahedra, edges with eighteen NaNa8Pm4 cuboctahedra, faces with eight equivalent PmNa12 cuboctahedra, and faces with twelve NaNa8Pm4 cuboctahedra.