DOE OSTI2020
Rh3Nb is Uranium Silicide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Nb is bonded to twelve Rh atoms to form NbRh12 cuboctahedra that share corners with six equivalent NbRh12 cuboctahedra, corners with twelve equivalent RhNb4Rh8 cuboctahedra, edges with eighteen RhNb4Rh8 cuboctahedra, faces with eight equivalent NbRh12 cuboctahedra, and faces with twelve RhNb4Rh8 cuboctahedra. There are six shorter (2.76 Å) and six longer (2.78 Å) Nb–Rh bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded to four equivalent Nb and eight equivalent Rh atoms to form distorted RhNb4Rh8 cuboctahedra that share corners with four equivalent NbRh12 cuboctahedra, corners with fourteen RhNb4Rh8 cuboctahedra, edges with six equivalent NbRh12 cuboctahedra, edges with twelve equivalent RhNb4Rh8 cuboctahedra, faces with four equivalent NbRh12 cuboctahedra, and faces with sixteen RhNb4Rh8 cuboctahedra. There are a spread of Rh–Rh bond distances ranging from 2.73–2.82 Å. In the second Rh site, Rh is bonded to four equivalent Nb and eight Rh atoms to form distorted RhNb4Rh8 cuboctahedra that share corners with four equivalent NbRh12 cuboctahedra, corners with fourteen RhNb4Rh8 cuboctahedra, edges with six equivalent NbRh12 cuboctahedra, edges with twelve RhNb4Rh8 cuboctahedra, faces with four equivalent NbRh12 cuboctahedra, and faces with sixteen RhNb4Rh8 cuboctahedra. There are a spread of Rh–Rh bond distances ranging from 2.73–2.82 Å.