Synthesis and crystal structure of a new layered carbide ZrAl4C4

A new ternary layered carbide, ZrAl4C4, has been synthesized and characterized by X-ray powder diffraction. The crystal structure was successfully determined using direct methods and further refined by the Rietveld method. The crystal is trigonal (space group P3m1, Z=2) with lattice dimensions a=0.332471(3) nm, c=2.19717(2) nm, and V=0.210330(3) nm(3). The final reliability indices calculated from the Rietveld refinement were R-wp=6.56% (S=1.58), R-p=4.92%, R-B=1.90%, and R-F=0.98%. The compound shows an intergrowth structure with NaCl-type [Zr2C3] thin slabs separated by Al4C3-type [Al8C7] layers.