Collect. Czech. Chem. Commun. 1988, 53, 2412-2417

Heat of interaction of oxygen with dysprosium and yttrium

Slavoj Černý and Milan Kovář

The J. Heyrovský Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, 182 23 Prague 8


Heat of interaction of oxygen dosed to vacuum-evaporated films of dysprosium and yttrium were measured in a calorimeter at room temperature. The high and rapidly produced heat, and the attained oxygen-to-metal ratio indicate high reactivity of these rare earth metals towards oxygen molecules which obviously undergo dissociative sorption. The energy of bonding of the formed oxygen species to the metal was estimated to 723 kJ/mol (173 kcal/mol) and 780 kJ/mol (186 kcal/mol) for Dy and Y, respectively. A markedly higher sorption capacity of Y film compared to Dy film was observed. The heat produced by the first admitted doses of oxygen may suggest formation of a solid solution of oxygen species in Dy and Y at very low oxygen-to-metal ratios.