Materials Data on Na3Cr by Materials Project
Na3Cr is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded to eight equivalent Na and four equivalent Cr atoms to form distorted NaNa8Cr4 cuboctahedra that share corners with eight equivalent CrNa12 cuboctahedra, corners with twenty NaNa8Cr4 cuboctahedra, edges with sixteen NaNa8Cr4 cuboctahedra, faces with four equivalent NaNa8Cr4 cuboctahedra, and faces with six equivalent CrNa12 cuboctahedra. All Na–Na bond lengths are 3.46 Å. All Na–Cr bond lengths are 3.51 Å. In the second Na site, Na is bonded to four equivalent Na and four equivalent Cr atoms to form distorted NaNa4Cr4 cuboctahedra that share corners with eight equivalent CrNa12 cuboctahedra, corners with sixteen NaNa8Cr4 cuboctahedra, edges with four equivalent CrNa12 cuboctahedra, edges with sixteen NaNa8Cr4 cuboctahedra, and faces with six equivalent NaNa4Cr4 cuboctahedra. All Na–Cr bond lengths are 3.46 Å. Cr is bonded to twelve Na atoms to form CrNa12 cuboctahedra that share corners with four equivalent CrNa12 cuboctahedra, corners with twenty-four NaNa8Cr4 cuboctahedra, edges with eight equivalent NaNa4Cr4 cuboctahedra, edges with eight equivalent CrNa12 cuboctahedra, faces with four equivalent CrNa12 cuboctahedra, and faces with six equivalent NaNa8Cr4 cuboctahedra.