Materials Data on Al8BC5 by Materials Project

Abstract

Al8BC5 is Aluminum carbonitride-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are four inequivalent Al sites. In the first Al site, Al is bonded to four C atoms to form a mixture of distorted edge and corner-sharing AlC4 tetrahedra. There are one shorter (1.93 Å) and three longer (2.20 Å) Al–C bond lengths. In the second Al site, Al is bonded to three equivalent B and one C atom to form distorted AlB3C tetrahedra that share corners with nine equivalent AlB3C tetrahedra, corners with four AlC4 trigonal pyramids, and edges with three equivalent AlB3C tetrahedra. All Al–B bond lengths are 2.21 Å. The Al–C bond length is 1.96 Å. In the third Al site, Al is bonded to four C atoms to form a mixture of edge and corner-sharing AlC4 trigonal pyramids. There are three shorter (1.97 Å) and one longer (2.23 Å) Al–C bond lengths. In the fourth Al site, Al is bonded to four C atoms to form a mixture of distorted edge and corner-sharing AlC4 trigonal pyramids. There are three shorter (1.99 Å) and one longer (2.14 Å) Al–C bond lengths. B is bonded to six equivalent Al atoms to form BAl6 octahedra that share corners with six equivalent CAl5 trigonal bipyramids and edges with six equivalent BAl6 octahedra. There are three inequivalent C sites. In the first C site, C is bonded to five Al atoms to form distorted CAl5 trigonal bipyramids that share corners with three equivalent CAl6 octahedra, corners with six equivalent CAl5 trigonal bipyramids, and edges with three equivalent CAl5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 63°. In the second C site, C is bonded to five Al atoms to form CAl5 trigonal bipyramids that share corners with three equivalent BAl6 octahedra, corners with six equivalent CAl5 trigonal bipyramids, and edges with three equivalent CAl5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. In the third C site, C is bonded to six equivalent Al atoms to form CAl6 octahedra that share corners with six equivalent CAl5 trigonal bipyramids and edges with six equivalent CAl6 octahedra.