Synthesis and crystal structure of a new layered carbide [Zr_1.97Y_0.03]Al₄C₅

Abstract

A new layered carbide, [Zr_1.97Y_0.03]Al₄C₅, 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 crystal structure was refined from laboratory X-ray powder diffraction data (CuKα₁) using the Rietveld method. The crystal is trigonal (space group R3m, Z = 3) with lattice dimensions of a = 0.331934(4) nm, c = 4.09459(3) nm and V = 0.390701(7) nm³. The compound shows an intergrowth structure with NaCl-type [Zr_1.97Y_0.03C₃] thin slabs separated by Al₄C₃-type [AlC] layers. This material is isostructural with Zr₂[Al_3.56Si_0.44]C₅.