DOE OSTI2020
YbYAl6 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Yb is bonded to twelve Al atoms to form YbAl12 cuboctahedra that share corners with six equivalent YbAl12 cuboctahedra, corners with twelve equivalent AlYb2Y2Al8 cuboctahedra, edges with six equivalent AlYb2Y2Al8 cuboctahedra, faces with two equivalent YbAl12 cuboctahedra, faces with six equivalent YAl12 cuboctahedra, and faces with six equivalent AlYb2Y2Al8 cuboctahedra. There are six shorter (3.04 Å) and six longer (3.07 Å) Yb–Al bond lengths. Y is bonded to twelve Al atoms to form YAl12 cuboctahedra that share corners with twelve equivalent YAl12 cuboctahedra, edges with twelve equivalent AlYb2Y2Al8 cuboctahedra, faces with six equivalent YbAl12 cuboctahedra, and faces with six equivalent AlYb2Y2Al8 cuboctahedra. There are six shorter (3.00 Å) and six longer (3.04 Å) Y–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to two equivalent Yb, two equivalent Y, and eight Al atoms to form distorted AlYb2Y2Al8 cuboctahedra that share corners with four equivalent YbAl12 cuboctahedra, corners with fourteen equivalent AlYb2Y2Al8 cuboctahedra, edges with two equivalent YbAl12 cuboctahedra, edges with four equivalent YAl12 cuboctahedra, edges with four equivalent AlYb2Y2Al8 cuboctahedra, faces with two equivalent YbAl12 cuboctahedra, faces with two equivalent YAl12 cuboctahedra, and faces with six equivalent AlYb2Y2Al8 cuboctahedra. There are four shorter (2.97 Å) and four longer (3.04 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 4-coordinate geometry to two equivalent Yb, two equivalent Y, and six Al atoms. Both Al–Al bond lengths are 2.84 Å.