Nb6IrAl11 crystallizes in the hexagonal P6_3/mcm space group. Nb(1) is bonded in a 16-coordinate geometry to four equivalent Nb(1), one Ir(1), two equivalent Al(2), three equivalent Al(3), and six equivalent Al(1) atoms. Ir(1) is bonded to six equivalent Nb(1) and six equivalent Al(3) atoms to form distorted IrNb6Al6 cuboctahedra that share corners with twelve equivalent Al(1)Nb6Al6 cuboctahedra, edges with six equivalent Al(2)Nb6Al6 cuboctahedra, faces with two equivalent Ir(1)Nb6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Nb6Al6 cuboctahedra. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to six equivalent Nb(1), one Al(3), two equivalent Al(2), and three equivalent Al(1) atoms to form AlNb6Al6 cuboctahedra that share corners with two equivalent Ir(1)Nb6Al6 cuboctahedra, corners with two equivalent Al(2)Nb6Al6 cuboctahedra, corners with eight equivalent Al(1)Nb6Al6 cuboctahedra, edges with three equivalent Al(1)Nb6Al6 cuboctahedra, faces with two equivalent Ir(1)Nb6Al6 cuboctahedra, faces with four equivalent Al(2)Nb6Al6 cuboctahedra, and faces with nine equivalent Al(1)Nb6Al6 cuboctahedra. In the second Al site, Al(2) is bonded to six equivalent Nb(1) and six equivalent Al(1) atoms to form AlNb6Al6 cuboctahedra that share corners with six equivalent Al(1)Nb6Al6 cuboctahedra, edges with three equivalent Ir(1)Nb6Al6 cuboctahedra, edges with three equivalent Al(2)Nb6Al6 cuboctahedra, faces with two equivalent Al(2)Nb6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Nb6Al6 cuboctahedra. In the third Al site, Al(3) is bonded in a distorted water-like geometry to six equivalent Nb(1), two equivalent Ir(1), and two equivalent Al(1) atoms.
Nb6IrAl11 crystallizes in the hexagonal P6_3/mcm space group. Nb(1) is bonded in a 16-coordinate geometry to four equivalent Nb(1), one Ir(1), two equivalent Al(2), three equivalent Al(3), and six equivalent Al(1) atoms. There are a spread of Nb(1)-Nb(1) bond distances ranging from 3.05-3.21 Å. The Nb(1)-Ir(1) bond length is 3.09 Å. Both Nb(1)-Al(2) bond lengths are 3.00 Å. There is one shorter (3.01 Å) and two longer (3.05 Å) Nb(1)-Al(3) bond lengths. There are two shorter (2.93 Å) and four longer (2.99 Å) Nb(1)-Al(1) bond lengths. Ir(1) is bonded to six equivalent Nb(1) and six equivalent Al(3) atoms to form distorted IrNb6Al6 cuboctahedra that share corners with twelve equivalent Al(1)Nb6Al6 cuboctahedra, edges with six equivalent Al(2)Nb6Al6 cuboctahedra, faces with two equivalent Ir(1)Nb6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Nb6Al6 cuboctahedra. All Ir(1)-Al(3) bond lengths are 2.54 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to six equivalent Nb(1), one Al(3), two equivalent Al(2), and three equivalent Al(1) atoms to form AlNb6Al6 cuboctahedra that share corners with two equivalent Ir(1)Nb6Al6 cuboctahedra, corners with two equivalent Al(2)Nb6Al6 cuboctahedra, corners with eight equivalent Al(1)Nb6Al6 cuboctahedra, edges with three equivalent Al(1)Nb6Al6 cuboctahedra, faces with two equivalent Ir(1)Nb6Al6 cuboctahedra, faces with four equivalent Al(2)Nb6Al6 cuboctahedra, and faces with nine equivalent Al(1)Nb6Al6 cuboctahedra. The Al(1)-Al(3) bond length is 2.52 Å. Both Al(1)-Al(2) bond lengths are 2.58 Å. There is one shorter (2.49 Å) and two longer (2.70 Å) Al(1)-Al(1) bond lengths. In the second Al site, Al(2) is bonded to six equivalent Nb(1) and six equivalent Al(1) atoms to form AlNb6Al6 cuboctahedra that share corners with six equivalent Al(1)Nb6Al6 cuboctahedra, edges with three equivalent Ir(1)Nb6Al6 cuboctahedra, edges with three equivalent Al(2)Nb6Al6 cuboctahedra, faces with two equivalent Al(2)Nb6Al6 cuboctahedra, and faces with twelve equivalent Al(1)Nb6Al6 cuboctahedra. In the third Al site, Al(3) is bonded in a distorted water-like geometry to six equivalent Nb(1), two equivalent Ir(1), and two equivalent Al(1) atoms.