Sc3Nb is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to four equivalent Sc(1), four equivalent Sc(2), and four equivalent Nb(1) atoms to form ScSc8Nb4 cuboctahedra that share corners with twelve equivalent Sc(1)Sc8Nb4 cuboctahedra, edges with eight equivalent Sc(1)Sc8Nb4 cuboctahedra, edges with eight equivalent Sc(2)Sc8Nb4 cuboctahedra, edges with eight equivalent Nb(1)Sc12 cuboctahedra, faces with four equivalent Sc(2)Sc8Nb4 cuboctahedra, faces with four equivalent Nb(1)Sc12 cuboctahedra, and faces with ten equivalent Sc(1)Sc8Nb4 cuboctahedra. In the second Sc site, Sc(2) is bonded to eight equivalent Sc(1) and four equivalent Nb(1) atoms to form ScSc8Nb4 cuboctahedra that share corners with four equivalent Sc(2)Sc8Nb4 cuboctahedra, corners with eight equivalent Nb(1)Sc12 cuboctahedra, edges with eight equivalent Sc(2)Sc8Nb4 cuboctahedra, edges with sixteen equivalent Sc(1)Sc8Nb4 cuboctahedra, faces with four equivalent Sc(2)Sc8Nb4 cuboctahedra, faces with six equivalent Nb(1)Sc12 cuboctahedra, and faces with eight equivalent Sc(1)Sc8Nb4 cuboctahedra. Nb(1) is bonded to four equivalent Sc(2) and eight equivalent Sc(1) atoms to form NbSc12 cuboctahedra that share corners with four equivalent Nb(1)Sc12 cuboctahedra, corners with eight equivalent Sc(2)Sc8Nb4 cuboctahedra, edges with eight equivalent Nb(1)Sc12 cuboctahedra, edges with sixteen equivalent Sc(1)Sc8Nb4 cuboctahedra, faces with four equivalent Nb(1)Sc12 cuboctahedra, faces with six equivalent Sc(2)Sc8Nb4 cuboctahedra, and faces with eight equivalent Sc(1)Sc8Nb4 cuboctahedra.
Sc3Nb is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded to four equivalent Sc(1), four equivalent Sc(2), and four equivalent Nb(1) atoms to form ScSc8Nb4 cuboctahedra that share corners with twelve equivalent Sc(1)Sc8Nb4 cuboctahedra, edges with eight equivalent Sc(1)Sc8Nb4 cuboctahedra, edges with eight equivalent Sc(2)Sc8Nb4 cuboctahedra, edges with eight equivalent Nb(1)Sc12 cuboctahedra, faces with four equivalent Sc(2)Sc8Nb4 cuboctahedra, faces with four equivalent Nb(1)Sc12 cuboctahedra, and faces with ten equivalent Sc(1)Sc8Nb4 cuboctahedra. All Sc(1)-Sc(1) bond lengths are 3.15 Å. All Sc(1)-Sc(2) bond lengths are 3.15 Å. All Sc(1)-Nb(1) bond lengths are 3.15 Å. In the second Sc site, Sc(2) is bonded to eight equivalent Sc(1) and four equivalent Nb(1) atoms to form ScSc8Nb4 cuboctahedra that share corners with four equivalent Sc(2)Sc8Nb4 cuboctahedra, corners with eight equivalent Nb(1)Sc12 cuboctahedra, edges with eight equivalent Sc(2)Sc8Nb4 cuboctahedra, edges with sixteen equivalent Sc(1)Sc8Nb4 cuboctahedra, faces with four equivalent Sc(2)Sc8Nb4 cuboctahedra, faces with six equivalent Nb(1)Sc12 cuboctahedra, and faces with eight equivalent Sc(1)Sc8Nb4 cuboctahedra. All Sc(2)-Nb(1) bond lengths are 3.15 Å. Nb(1) is bonded to four equivalent Sc(2) and eight equivalent Sc(1) atoms to form NbSc12 cuboctahedra that share corners with four equivalent Nb(1)Sc12 cuboctahedra, corners with eight equivalent Sc(2)Sc8Nb4 cuboctahedra, edges with eight equivalent Nb(1)Sc12 cuboctahedra, edges with sixteen equivalent Sc(1)Sc8Nb4 cuboctahedra, faces with four equivalent Nb(1)Sc12 cuboctahedra, faces with six equivalent Sc(2)Sc8Nb4 cuboctahedra, and faces with eight equivalent Sc(1)Sc8Nb4 cuboctahedra.