Eu3Nb is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Eu(1) is bonded to eight equivalent Eu(1) and four equivalent Nb(1) atoms to form distorted EuEu8Nb4 cuboctahedra that share corners with four equivalent Nb(1)Eu12 cuboctahedra, corners with fourteen equivalent Eu(1)Eu8Nb4 cuboctahedra, edges with six equivalent Nb(1)Eu12 cuboctahedra, edges with twelve equivalent Eu(1)Eu8Nb4 cuboctahedra, faces with four equivalent Nb(1)Eu12 cuboctahedra, and faces with sixteen equivalent Eu(1)Eu8Nb4 cuboctahedra. Nb(1) is bonded to twelve equivalent Eu(1) atoms to form NbEu12 cuboctahedra that share corners with six equivalent Nb(1)Eu12 cuboctahedra, corners with twelve equivalent Eu(1)Eu8Nb4 cuboctahedra, edges with eighteen equivalent Eu(1)Eu8Nb4 cuboctahedra, faces with eight equivalent Nb(1)Eu12 cuboctahedra, and faces with twelve equivalent Eu(1)Eu8Nb4 cuboctahedra.
Eu3Nb is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Eu(1) is bonded to eight equivalent Eu(1) and four equivalent Nb(1) atoms to form distorted EuEu8Nb4 cuboctahedra that share corners with four equivalent Nb(1)Eu12 cuboctahedra, corners with fourteen equivalent Eu(1)Eu8Nb4 cuboctahedra, edges with six equivalent Nb(1)Eu12 cuboctahedra, edges with twelve equivalent Eu(1)Eu8Nb4 cuboctahedra, faces with four equivalent Nb(1)Eu12 cuboctahedra, and faces with sixteen equivalent Eu(1)Eu8Nb4 cuboctahedra. There are a spread of Eu(1)-Eu(1) bond distances ranging from 3.31-3.65 Å. There are two shorter (3.36 Å) and two longer (3.48 Å) Eu(1)-Nb(1) bond lengths. Nb(1) is bonded to twelve equivalent Eu(1) atoms to form NbEu12 cuboctahedra that share corners with six equivalent Nb(1)Eu12 cuboctahedra, corners with twelve equivalent Eu(1)Eu8Nb4 cuboctahedra, edges with eighteen equivalent Eu(1)Eu8Nb4 cuboctahedra, faces with eight equivalent Nb(1)Eu12 cuboctahedra, and faces with twelve equivalent Eu(1)Eu8Nb4 cuboctahedra.