Actinium heat capacity

Thermodynamic measurements that have been made on the actinide metals are low- and high-temperature heat capacities, properties of phase transitions, and vapor pressures. At least one of these measurements has been made on each element through einsteinium unfortunately, however, none has been made on actinium, so that even its enthalpy of vaporization must be estimated. As of the time of writing (February 1986) vapor-pressure measurements have been made through einsteinium [22] and low-temperature heat-capacity measurements through americium [23] by innovative microscale methods, innovative microscale methods have been applied to determine vapor pressures and very low-temperature heat capacities of transplutonium actinides. 

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