Materials Data on Mg(AlC)2 by Materials Project
Al2MgC2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Mg2+ is bonded to six equivalent C4- atoms to form MgC6 octahedra that share corners with twelve equivalent AlC4 tetrahedra, edges with six equivalent MgC6 octahedra, and edges with six equivalent AlC4 tetrahedra. All Mg–C bond lengths are 2.51 Å. Al3+ is bonded to four equivalent C4- atoms to form AlC4 tetrahedra that share corners with six equivalent MgC6 octahedra, corners with six equivalent AlC4 tetrahedra, edges with three equivalent MgC6 octahedra, and edges with three equivalent AlC4 tetrahedra. The corner-sharing octahedra tilt angles range from 25–51°. There are three shorter (2.01 Å) and one longer (2.21 Å) Al–C bond lengths. C4- is bonded in a 7-coordinate geometry to three equivalent Mg2+ and four equivalent Al3+ atoms.