Mass-spectrometric study of PuCd2

PuCd2 intermetallic compound was prepared by heating pure Pu and Cd metals at ∼950 K. Plutonium metal used in the preparation of PuCd2 was prepared by the tantalothermic reduction of Pu2C3 followed by selective evaporation. PuCd2 is found to be a prototype of CdI2 by means of powder X-ray diffractometry as in the cases of CeCd2 and LaCd2. Mass-spectrometric experiment was performed in the temperature range of 650-770 K. It is found that the vapor pressures of Cd over PuCd2+Pu are three to five orders of magnitude lower than those over pure Cd in this temperature range. From these vapor pressures, Gibbs free energy of formation of PuCd2 is evaluated.