DOE OSTI2020
Be3Nb crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Be sites. In the first Be site, Be is bonded to six equivalent Be and six equivalent Nb atoms to form BeBe6Nb6 cuboctahedra that share corners with twelve equivalent BeBe7Nb5 cuboctahedra, edges with six equivalent BeBe6Nb6 cuboctahedra, and faces with eighteen equivalent BeBe7Nb5 cuboctahedra. All Be–Be bond lengths are 2.25 Å. All Be–Nb bond lengths are 2.69 Å. In the second Be site, Be is bonded in a 12-coordinate geometry to six equivalent Be and three equivalent Nb atoms. There are three shorter (2.15 Å) and three longer (2.16 Å) Be–Be bond lengths. All Be–Nb bond lengths are 2.64 Å. In the third Be site, Be is bonded to seven Be and five Nb atoms to form distorted BeBe7Nb5 cuboctahedra that share corners with seventeen BeBe6Nb6 cuboctahedra, edges with eight equivalent BeBe7Nb5 cuboctahedra, and faces with fourteen BeBe6Nb6 cuboctahedra. There are two shorter (2.25 Å) and two longer (2.32 Å) Be–Be bond lengths. There are a spread of Be–Nb bond distances ranging from 2.60–2.85 Å. There are two inequivalent Nb sites. In the first Nb site, Nb is bonded in a 6-coordinate geometry to eighteen Be and two equivalent Nb atoms. Both Nb–Nb bond lengths are 2.96 Å. In the second Nb site, Nb is bonded in a 12-coordinate geometry to twelve Be and four Nb atoms. All Nb–Nb bond lengths are 2.86 Å.