Y2Co3Al crystallizes in the trigonal R-3m space group. Y(1) is bonded in a 16-coordinate geometry to four equivalent Y(1), nine equivalent Co(1), and three equivalent Al(1) atoms. Co(1) is bonded to six equivalent Y(1), four equivalent Co(1), and two equivalent Al(1) atoms to form distorted CoY6Al2Co4 cuboctahedra that share corners with four equivalent Al(1)Y6Co6 cuboctahedra, corners with fourteen equivalent Co(1)Y6Al2Co4 cuboctahedra, edges with six equivalent Co(1)Y6Al2Co4 cuboctahedra, faces with six equivalent Al(1)Y6Co6 cuboctahedra, and faces with twelve equivalent Co(1)Y6Al2Co4 cuboctahedra. Al(1) is bonded to six equivalent Y(1) and six equivalent Co(1) atoms to form distorted AlY6Co6 cuboctahedra that share corners with six equivalent Al(1)Y6Co6 cuboctahedra, corners with twelve equivalent Co(1)Y6Al2Co4 cuboctahedra, edges with six equivalent Al(1)Y6Co6 cuboctahedra, and faces with eighteen equivalent Co(1)Y6Al2Co4 cuboctahedra.
Y2Co3Al crystallizes in the trigonal R-3m space group. Y(1) is bonded in a 16-coordinate geometry to four equivalent Y(1), nine equivalent Co(1), and three equivalent Al(1) atoms. There is one shorter (3.02 Å) and three longer (3.22 Å) Y(1)-Y(1) bond lengths. There are three shorter (2.86 Å) and six longer (3.08 Å) Y(1)-Co(1) bond lengths. All Y(1)-Al(1) bond lengths are 3.13 Å. Co(1) is bonded to six equivalent Y(1), four equivalent Co(1), and two equivalent Al(1) atoms to form distorted CoY6Al2Co4 cuboctahedra that share corners with four equivalent Al(1)Y6Co6 cuboctahedra, corners with fourteen equivalent Co(1)Y6Al2Co4 cuboctahedra, edges with six equivalent Co(1)Y6Al2Co4 cuboctahedra, faces with six equivalent Al(1)Y6Co6 cuboctahedra, and faces with twelve equivalent Co(1)Y6Al2Co4 cuboctahedra. All Co(1)-Co(1) bond lengths are 2.68 Å. Both Co(1)-Al(1) bond lengths are 2.49 Å. Al(1) is bonded to six equivalent Y(1) and six equivalent Co(1) atoms to form distorted AlY6Co6 cuboctahedra that share corners with six equivalent Al(1)Y6Co6 cuboctahedra, corners with twelve equivalent Co(1)Y6Al2Co4 cuboctahedra, edges with six equivalent Al(1)Y6Co6 cuboctahedra, and faces with eighteen equivalent Co(1)Y6Al2Co4 cuboctahedra.