DOE OSTI2020
La3Nb is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent La sites. In the first La site, La is bonded to eight La and four equivalent Nb atoms to form distorted LaLa8Nb4 cuboctahedra that share corners with twelve equivalent LaLa8Nb4 cuboctahedra, edges with eight equivalent NbLa12 cuboctahedra, edges with sixteen LaLa8Nb4 cuboctahedra, faces with four equivalent NbLa12 cuboctahedra, and faces with fourteen LaLa8Nb4 cuboctahedra. There are four shorter (3.45 Å) and four longer (3.49 Å) La–La bond lengths. All La–Nb bond lengths are 3.45 Å. In the second La site, La is bonded to eight equivalent La and four equivalent Nb atoms to form LaLa8Nb4 cuboctahedra that share corners with four equivalent LaLa8Nb4 cuboctahedra, corners with eight equivalent NbLa12 cuboctahedra, edges with twenty-four LaLa8Nb4 cuboctahedra, faces with six equivalent NbLa12 cuboctahedra, and faces with twelve LaLa8Nb4 cuboctahedra. All La–Nb bond lengths are 3.49 Å. Nb is bonded to twelve La atoms to form NbLa12 cuboctahedra that share corners with four equivalent NbLa12 cuboctahedra, corners with eight equivalent LaLa8Nb4 cuboctahedra, edges with eight equivalent NbLa12 cuboctahedra, edges with sixteen equivalent LaLa8Nb4 cuboctahedra, faces with four equivalent NbLa12 cuboctahedra, and faces with fourteen LaLa8Nb4 cuboctahedra.