[Zr0.72Y0.28]Al4C4: A new member of the homologous series (MC)l(T4C3)m (M=Zr, Y and Hf, T=Al, Si and Ge)

A new layered carbide, [Zr0.72(3)Y0.28(3)]Al4C4, has been synthesized and characterized by X-ray powder diffraction, transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX). The atom ratios [Zr:Y] were determined by EDX, and the initial structure model was derived by the direct methods, and further refined by Rietveld method. The crystal is trigonal (space group View the MathML sourceP3¯m1, Z=1) with lattice dimensions of a=0.333990(5) nm, c=1.09942(1) nm and V=0.106209(2) nm3. This compound shows an intergrowth structure with [Zr0.72Y0.28C2] thin slabs separated by Al4C3-type [Al4C4] layers. It is a new member with l=1 and m=1 of the homologous series, the general formula of which is (MC)l(T4C3)m (l=1, 2 and 3, m=1 and 2, M=Zr, Y and Hf, T=Al, Si and Ge).