Y3Ni8Al crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to three equivalent Ni(2), six equivalent Ni(1), and three equivalent Al(1) atoms to form YAl3Ni9 cuboctahedra that share corners with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra, corners with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, edges with six equivalent Y(1)Al3Ni9 cuboctahedra, edges with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, faces with two equivalent Ni(3)Y6Ni6 cuboctahedra, and faces with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra. In the second Y site, Y(2) is bonded in a 13-coordinate geometry to three equivalent Ni(3), nine equivalent Ni(1), and one Al(1) atom. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 10-coordinate geometry to one Y(1), three equivalent Y(2), one Ni(2), one Ni(3), and four equivalent Ni(1) atoms. In the second Ni site, Ni(2) is bonded to three equivalent Y(1), six equivalent Ni(1), and three equivalent Al(1) atoms to form NiY3Al3Ni6 cuboctahedra that share corners with three equivalent Y(1)Al3Ni9 cuboctahedra, corners with six equivalent Ni(3)Y6Ni6 cuboctahedra, corners with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, edges with six equivalent Ni(2)Y3Al3Ni6 cuboctahedra, edges with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, and faces with three equivalent Y(1)Al3Ni9 cuboctahedra. In the third Ni site, Ni(3) is bonded to six equivalent Y(2) and six equivalent Ni(1) atoms to form NiY6Ni6 cuboctahedra that share corners with six equivalent Ni(2)Y3Al3Ni6 cuboctahedra, corners with six equivalent Al(1)Y5Ni3 hexagonal bipyramids, edges with six equivalent Ni(3)Y6Ni6 cuboctahedra, and faces with two equivalent Y(1)Al3Ni9 cuboctahedra. Al(1) is bonded to two equivalent Y(2), three equivalent Y(1), and three equivalent Ni(2) atoms to form distorted AlY5Ni3 hexagonal bipyramids that share corners with three equivalent Y(1)Al3Ni9 cuboctahedra, corners with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra, corners with six equivalent Ni(3)Y6Ni6 cuboctahedra, edges with three equivalent Y(1)Al3Ni9 cuboctahedra, edges with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra, and edges with six equivalent Al(1)Y5Ni3 hexagonal bipyramids.
Y3Ni8Al crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to three equivalent Ni(2), six equivalent Ni(1), and three equivalent Al(1) atoms to form YAl3Ni9 cuboctahedra that share corners with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra, corners with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, edges with six equivalent Y(1)Al3Ni9 cuboctahedra, edges with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, faces with two equivalent Ni(3)Y6Ni6 cuboctahedra, and faces with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra. All Y(1)-Ni(2) bond lengths are 2.93 Å. All Y(1)-Ni(1) bond lengths are 2.67 Å. All Y(1)-Al(1) bond lengths are 2.93 Å. In the second Y site, Y(2) is bonded in a 13-coordinate geometry to three equivalent Ni(3), nine equivalent Ni(1), and one Al(1) atom. All Y(2)-Ni(3) bond lengths are 3.03 Å. There are six shorter (2.80 Å) and three longer (3.07 Å) Y(2)-Ni(1) bond lengths. The Y(2)-Al(1) bond length is 3.36 Å. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 10-coordinate geometry to one Y(1), three equivalent Y(2), one Ni(2), one Ni(3), and four equivalent Ni(1) atoms. The Ni(1)-Ni(2) bond length is 2.59 Å. The Ni(1)-Ni(3) bond length is 2.48 Å. There are two shorter (2.42 Å) and two longer (2.65 Å) Ni(1)-Ni(1) bond lengths. In the second Ni site, Ni(2) is bonded to three equivalent Y(1), six equivalent Ni(1), and three equivalent Al(1) atoms to form NiY3Al3Ni6 cuboctahedra that share corners with three equivalent Y(1)Al3Ni9 cuboctahedra, corners with six equivalent Ni(3)Y6Ni6 cuboctahedra, corners with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, edges with six equivalent Ni(2)Y3Al3Ni6 cuboctahedra, edges with three equivalent Al(1)Y5Ni3 hexagonal bipyramids, and faces with three equivalent Y(1)Al3Ni9 cuboctahedra. All Ni(2)-Al(1) bond lengths are 2.93 Å. In the third Ni site, Ni(3) is bonded to six equivalent Y(2) and six equivalent Ni(1) atoms to form NiY6Ni6 cuboctahedra that share corners with six equivalent Ni(2)Y3Al3Ni6 cuboctahedra, corners with six equivalent Al(1)Y5Ni3 hexagonal bipyramids, edges with six equivalent Ni(3)Y6Ni6 cuboctahedra, and faces with two equivalent Y(1)Al3Ni9 cuboctahedra. Al(1) is bonded to two equivalent Y(2), three equivalent Y(1), and three equivalent Ni(2) atoms to form distorted AlY5Ni3 hexagonal bipyramids that share corners with three equivalent Y(1)Al3Ni9 cuboctahedra, corners with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra, corners with six equivalent Ni(3)Y6Ni6 cuboctahedra, edges with three equivalent Y(1)Al3Ni9 cuboctahedra, edges with three equivalent Ni(2)Y3Al3Ni6 cuboctahedra, and edges with six equivalent Al(1)Y5Ni3 hexagonal bipyramids.