Materials Data on Nb3AlC2 by Materials Project
Nb3AlC2 is MAX Phase-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Nb sites. In the first Nb site, Nb is bonded in a 3-coordinate geometry to three equivalent Al and three equivalent C atoms. All Nb–Al bond lengths are 2.88 Å. All Nb–C bond lengths are 2.19 Å. In the second Nb site, Nb is bonded to six equivalent C atoms to form edge-sharing NbC6 octahedra. All Nb–C bond lengths are 2.25 Å. Al is bonded to six equivalent Nb atoms to form distorted AlNb6 cuboctahedra that share corners with six equivalent CNb6 octahedra, edges with six equivalent AlNb6 cuboctahedra, and edges with six equivalent CNb6 octahedra. The corner-sharing octahedral tilt angles are 17°. C is bonded to six Nb atoms to form CNb6 octahedra that share corners with three equivalent AlNb6 cuboctahedra, corners with three equivalent CNb6 octahedra, edges with three equivalent AlNb6 cuboctahedra, and edges with nine equivalent CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°.