Materials Data on Zr4(AlC2)3 by Materials Project

Abstract

Zr4(AlC2)3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Zr+3.75+ sites. In the first Zr+3.75+ site, Zr+3.75+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing ZrC6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are three shorter (2.36 Å) and three longer (2.41 Å) Zr–C bond lengths. In the second Zr+3.75+ site, Zr+3.75+ is bonded to six C4- atoms to form ZrC6 octahedra that share corners with three equivalent ZrC6 octahedra, corners with three equivalent AlC4 tetrahedra, edges with nine ZrC6 octahedra, and edges with three equivalent AlC4 tetrahedra. The corner-sharing octahedral tilt angles are 3°. There are three shorter (2.31 Å) and three longer (2.51 Å) Zr–C bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four C4- atoms to form AlC4 tetrahedra that share corners with three equivalent ZrC6 octahedra, corners with seven equivalent AlC4 tetrahedra, and edges with three equivalent ZrC6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are one shorter (2.02 Å) and three longer (2.06 Å) Al–C bond lengths. In the second Al3+ site, Al3+ is bonded in a trigonal planar geometry to three equivalent C4- atoms. All Al–C bond lengths are 1.94 Å. There are four inequivalent C4- sites. In the first C4- site, C4- is bonded to six Zr+3.75+ atoms to form a mixture of edge and corner-sharing CZr6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second C4- site, C4- is bonded in a 6-coordinate geometry to three equivalent Zr+3.75+ and three equivalent Al3+ atoms. In the third C4- site, C4- is bonded to five Al3+ atoms to form corner-sharing CAl5 trigonal bipyramids. In the fourth C4- site, C4- is bonded to six equivalent Zr+3.75+ atoms to form a mixture of edge and corner-sharing CZr6 octahedra. The corner-sharing octahedral tilt angles are 2°.