Collect. Czech. Chem. Commun. 1985, 50, 1153-1160

Roentgenographic and thermodynamic study of the existence of mixed crystals in the LaC2-YC2 system

Bohumil Hájek, Vladimír Kohout and Vratislav Flemr

Department of Inorganic Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


The reaction heats for the mixed crystal formation in the LaC2-YC2 system were obtained from the equilibrium gas pressures measured during the carboreduction. The low positive values of the reaction heats are consistent with the X-ray diffraction study of the carbothermal reduction products of the oxides, where the formation of the (La, Y)C2 dicarbide mixed crystals was only observed in the two side regions up to 25 mol.% of each of the minority components. The composition of the gaseous hydrolysis products of the (La, Y)C2 mixed crystals corresponds to the hydrolysis products of the dicarbide. No methane was detected for samples with low yttrium contents.