Synthesis and crystal structure of La₂₁Cr_8−2a Al _b Ge_7−b C₁₂ [a = 0.22 (2) and b = 0.758 (19)]

Abstract

The face-centered cubic crystal structure of a new multinary chromium carbide, La21Cr8−2aAlbGe7−bC12, is composed of isolated and geometrically frustrated regular Cr tetra­hedra that are co-centered within regular C octa­hedra. These mutually separated Cr4−aC6 clusters are distributed throughout a three-dimensional framework of Al, Ge, and La.