Nb4AlC3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent C(1) atoms. In the second Nb site, Nb(2) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form a mixture of corner and edge-sharing NbC6 octahedra. The corner-sharing octahedra are not tilted. Al(1) is bonded in a 6-coordinate geometry to six equivalent Nb(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C site, C(2) is bonded to six equivalent Nb(2) atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°.
Nb4AlC3 is MAX Phase structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 3-coordinate geometry to three equivalent Al(1) and three equivalent C(1) atoms. All Nb(1)-Al(1) bond lengths are 2.90 Å. All Nb(1)-C(1) bond lengths are 2.17 Å. In the second Nb site, Nb(2) is bonded to three equivalent C(1) and three equivalent C(2) atoms to form a mixture of corner and edge-sharing NbC6 octahedra. The corner-sharing octahedra are not tilted. All Nb(2)-C(1) bond lengths are 2.24 Å. All Nb(2)-C(2) bond lengths are 2.27 Å. Al(1) is bonded in a 6-coordinate geometry to six equivalent Nb(1) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded to three equivalent Nb(1) and three equivalent Nb(2) atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C site, C(2) is bonded to six equivalent Nb(2) atoms to form a mixture of corner and edge-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°.