Y5Ir3 crystallizes in the tetragonal P4/ncc space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent Ir(2) and three equivalent Ir(1) atoms to form distorted YIr5 trigonal bipyramids that share corners with four equivalent Y(2)Ir4 tetrahedra, corners with eleven equivalent Y(1)Ir5 trigonal bipyramids,  an edgeedge with one Y(2)Ir4 tetrahedra, edges with six equivalent Y(1)Ir5 trigonal bipyramids, and faces with two equivalent Y(1)Ir5 trigonal bipyramids. In the second Y site, Y(2) is bonded to four equivalent Ir(1) atoms to form YIr4 tetrahedra that share corners with sixteen equivalent Y(1)Ir5 trigonal bipyramids, edges with two equivalent Y(2)Ir4 tetrahedra, and edges with four equivalent Y(1)Ir5 trigonal bipyramids. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 8-coordinate geometry to two equivalent Y(2) and six equivalent Y(1) atoms. In the second Ir site, Ir(2) is bonded in a 8-coordinate geometry to eight equivalent Y(1) atoms.
Y5Ir3 crystallizes in the tetragonal P4/ncc space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to two equivalent Ir(2) and three equivalent Ir(1) atoms to form distorted YIr5 trigonal bipyramids that share corners with four equivalent Y(2)Ir4 tetrahedra, corners with eleven equivalent Y(1)Ir5 trigonal bipyramids,  an edgeedge with one Y(2)Ir4 tetrahedra, edges with six equivalent Y(1)Ir5 trigonal bipyramids, and faces with two equivalent Y(1)Ir5 trigonal bipyramids. There is one shorter (2.92 Å) and one longer (2.94 Å) Y(1)-Ir(2) bond length. There are a spread of Y(1)-Ir(1) bond distances ranging from 2.87-3.15 Å. In the second Y site, Y(2) is bonded to four equivalent Ir(1) atoms to form YIr4 tetrahedra that share corners with sixteen equivalent Y(1)Ir5 trigonal bipyramids, edges with two equivalent Y(2)Ir4 tetrahedra, and edges with four equivalent Y(1)Ir5 trigonal bipyramids. All Y(2)-Ir(1) bond lengths are 2.85 Å. There are two inequivalent Ir sites. In the first Ir site, Ir(1) is bonded in a 8-coordinate geometry to two equivalent Y(2) and six equivalent Y(1) atoms. In the second Ir site, Ir(2) is bonded in a 8-coordinate geometry to eight equivalent Y(1) atoms.