New ternary compound La_8Al_(13)Sn_3

摘要

A new ternary compound La8Al13Sn3 was synthesized and studied by means of X-ray powder diffraction technique. The compound La8Al13Sn3 crystallizes in a hexagonal AlB2-type structure with space group P6/mmm (No. 191) and the lattice parameters a = 0.44919(1) nm and c = 0.43835(1) nm. The Smith and Snyder figure of merit for index, FN, is F30 = 197.3(30). The Rietveld refinement for the crystal structure of the compound was carried out successfully. The liability R-factors of Rietveld refinement are Rp = 0.114 and Rwp = 0.148. The compound La8Al13Sn3 decomposes into LaAl2 with cubic structure and space group Fd 3m (227), LaAl3 with hexagonal structure and space group P63/mmc (194), and Sn at 720°C.