Zr3Al3C5 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form ZrC6 octahedra that share corners with three equivalent Zr(2)C6 octahedra, corners with three equivalent Al(2)C4 tetrahedra, edges with three equivalent Zr(2)C6 octahedra, edges with six equivalent Zr(1)C6 octahedra, and edges with three equivalent Al(2)C4 tetrahedra. The corner-sharing octahedral tilt angles are 3°. In the second Zr site, Zr(2) is bonded to six equivalent C(1) atoms to form a mixture of corner and edge-sharing ZrC6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a trigonal planar geometry to three equivalent C(3) atoms. In the second Al site, Al(2) is bonded to one C(3) and three equivalent C(2) atoms to form AlC4 tetrahedra that share corners with three equivalent Zr(1)C6 octahedra, corners with seven equivalent Al(2)C4 tetrahedra, and edges with three equivalent Zr(1)C6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are three inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Zr(1) and three equivalent Zr(2) atoms to form a mixture of corner and edge-sharing CZr6 octahedra. The corner-sharing octahedra are not tilted. In the second C site, C(2) is bonded in a 6-coordinate geometry to three equivalent Zr(1) and three equivalent Al(2) atoms. In the third C site, C(3) is bonded to two equivalent Al(2) and three equivalent Al(1) atoms to form corner-sharing CAl5 trigonal bipyramids.
Zr3Al3C5 crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Zr sites. In the first Zr site, Zr(1) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form ZrC6 octahedra that share corners with three equivalent Zr(2)C6 octahedra, corners with three equivalent Al(2)C4 tetrahedra, edges with three equivalent Zr(2)C6 octahedra, edges with six equivalent Zr(1)C6 octahedra, and edges with three equivalent Al(2)C4 tetrahedra. The corner-sharing octahedral tilt angles are 3°. All Zr(1)-C(1) bond lengths are 2.30 Å. All Zr(1)-C(2) bond lengths are 2.49 Å. In the second Zr site, Zr(2) is bonded to six equivalent C(1) atoms to form a mixture of corner and edge-sharing ZrC6 octahedra. The corner-sharing octahedral tilt angles are 3°. All Zr(2)-C(1) bond lengths are 2.38 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded in a trigonal planar geometry to three equivalent C(3) atoms. All Al(1)-C(3) bond lengths are 1.93 Å. In the second Al site, Al(2) is bonded to one C(3) and three equivalent C(2) atoms to form AlC4 tetrahedra that share corners with three equivalent Zr(1)C6 octahedra, corners with seven equivalent Al(2)C4 tetrahedra, and edges with three equivalent Zr(1)C6 octahedra. The corner-sharing octahedral tilt angles are 20°. The Al(2)-C(3) bond length is 2.00 Å. All Al(2)-C(2) bond lengths are 2.05 Å. There are three inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Zr(1) and three equivalent Zr(2) atoms to form a mixture of corner and edge-sharing CZr6 octahedra. The corner-sharing octahedra are not tilted. In the second C site, C(2) is bonded in a 6-coordinate geometry to three equivalent Zr(1) and three equivalent Al(2) atoms. In the third C site, C(3) is bonded to two equivalent Al(2) and three equivalent Al(1) atoms to form corner-sharing CAl5 trigonal bipyramids.