The enthalpy of solution of 243Am metal and the standard enthalpy of formation of Am3+(aq)

Abstract The enthalpy of solution of americium metal (double hexagonal close packed) in l M HCl has been measured at 298.15 ± 0.05 K giving a value of-620.6±1.3 kJ mol −1 . From this value, the standard enthalpy of formation of Am 3+ (aq), Δ H f 0 (Am 3+ , aq), is derived as−621.2 ± 2.0 kJ mol −1 , and using reasonable entropy estimates, the standard potential of the Am 3+ /Am 0 couple is calculated to be-2.08±0.01 V.