A definition will appear here.
The values of ΔHf8 and ΔGf8 represent the changes in H or G when one mole of the element is formed in the defined state isothermally from the elements in its appropriate standard state. The standard state is chosen to be the state that is thermodynamically stable at 258C and 1 atmosphere pressure. The standard state is shown as those for which ΔHf and ΔGf are precisely zero.
The values of S8 represent the virtual of thermal "entropy" of the element in the standard state at 298.15 K, omitting contributions from nuclear spins and isotope mixing effects.
The heat capacity, Cp8, is the quantity of heat required to increase the temperature by 1 K of one mole of the element in the defined state. The units are J K-1 mol-1. This quantity is dependent upon temperature in a complex fashion. See Ref. 2 for further details.
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