DOI: 10.17188/1654123
title: Materials Data on Al9SiC7N by Materials Project

description: Al9SiC7N is Aluminum carbonitride-derived structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are nine inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to one C4- and three equivalent N3- atoms to form AlCN3 tetrahedra that share corners with nine AlCN3 tetrahedra and corners with four AlC4 trigonal pyramids. The Al–C bond length is 1.93 Å. All Al–N bond lengths are 2.04 Å. In the second Al3+ site, Al3+ is bonded to four C4- atoms to form a mixture of corner and edge-sharing AlC4 tetrahedra. There are three shorter (1.96 Å) and one longer (2.15 Å) Al–C bond lengths. In the third Al3+ site, Al3+ is bonded to four C4- atoms to form distorted AlC4 trigonal pyramids that share corners with four AlCN3 tetrahedra, corners with six equivalent AlC4 trigonal pyramids, and edges with three equivalent AlC4 trigonal pyramids. There are three shorter (1.95 Å) and one longer (2.20 Å) Al–C bond lengths. In the fourth Al3+ site, Al3+ is bonded to four C4- atoms to form a mixture of distorted corner and edge-sharing AlC4 trigonal pyramids. There are three shorter (1.94 Å) and one longer (2.26 Å) Al–C bond lengths. In the fifth Al3+ site, Al3+ is bonded to four C4- atoms to form a mixture of distorted corner and edge-sharing AlC4 trigonal pyramids. There are three shorter (1.95 Å) and one longer (2.20 Å) Al–C bond lengths. In the sixth Al3+ site, Al3+ is bonded to four C4- atoms to form AlC4 tetrahedra that share corners with three equivalent SiC4 tetrahedra, corners with seven AlC4 tetrahedra, and corners with three equivalent AlC4 trigonal pyramids. There are one shorter (2.00 Å) and three longer (2.03 Å) Al–C bond lengths. In the seventh Al3+ site, Al3+ is bonded to three equivalent C4- and one N3- atom to form distorted AlC3N tetrahedra that share corners with three equivalent SiC4 tetrahedra, corners with nine AlCN3 tetrahedra, and edges with three equivalent SiC4 tetrahedra. All Al–C bond lengths are 2.16 Å. The Al–N bond length is 1.83 Å. In the eighth Al3+ site, Al3+ is bonded to four C4- atoms to form a mixture of corner and edge-sharing AlC4 tetrahedra. There are one shorter (1.93 Å) and three longer (2.17 Å) Al–C bond lengths. In the ninth Al3+ site, Al3+ is bonded to four C4- atoms to form a mixture of corner and edge-sharing AlC4 tetrahedra. There are one shorter (1.94 Å) and three longer (2.17 Å) Al–C bond lengths. Si4+ is bonded to four C4- atoms to form distorted SiC4 tetrahedra that share corners with six AlC4 tetrahedra, corners with six equivalent SiC4 tetrahedra, and edges with three equivalent AlC3N tetrahedra. There is one shorter (1.73 Å) and three longer (2.17 Å) Si–C bond length. There are seven inequivalent C4- sites. In the first C4- site, C4- is bonded to five Al3+ atoms to form distorted CAl5 trigonal bipyramids that share corners with three equivalent NAl4 tetrahedra, corners with six equivalent CAl5 trigonal bipyramids, and edges with three equivalent CAl5 trigonal bipyramids. In the second C4- site, C4- is bonded to five Al3+ atoms to form CAl5 trigonal bipyramids that share corners with three equivalent CAl3Si tetrahedra, corners with six equivalent CAl5 trigonal bipyramids, and edges with three equivalent CAl5 trigonal bipyramids. In the third C4- site, C4- is bonded to five Al3+ 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 62°. In the fourth C4- site, C4- is bonded to three equivalent Al3+ and one Si4+ atom to form CAl3Si tetrahedra that share corners with three equivalent CAl3Si3 octahedra, corners with six equivalent CAl3Si tetrahedra, and corners with three equivalent CAl5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. In the fifth C4- site, C4- is bonded to three equivalent Al3+ and three equivalent Si4+ atoms to form distorted CAl3Si3 octahedra that share corners with three equivalent CAl3Si tetrahedra, corners with three equivalent NAl4 tetrahedra, and edges with six equivalent CAl3Si3 octahedra. In the sixth C4- site, C4- is bonded to six Al3+ atoms to form CAl6 octahedra that share corners with six CAl5 trigonal bipyramids and edges with six equivalent CAl6 octahedra. In the seventh C4- site, C4- is bonded to five Al3+ 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 62°. N3- is bonded to four Al3+ atoms to form NAl4 tetrahedra that share corners with three equivalent CAl3Si3 octahedra, corners with six equivalent NAl4 tetrahedra, and corners with three equivalent CAl5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 63°.