chemical thermodynamics of neptunium and plutonium - U.S. ...

2.1 Symbols, terminology and nomenclature 15Table 2.3: Abbreviations used as subscripts of to denote the type of chemical processes.Subscript of atdehyddilffushydmixrsolsubtrtrsvapChemical processseparation of a substance into its constituent gaseous atoms(atomisation)elimination of water of hydration (dehydration)dilution of a solutionformation of a compound from its constituent elementsmelting (fusion) of a solidaddition of water of hydration to an unhydrated compoundmixing of fluidschemical reaction (general)process of dissolutionsublimation (evaporation) of a solidtransfer from one solution or liquid phase to anothertransition of one solid phase to anothervaporisation (evaporation) of a liquid2.1.5 ProcessesChemical processes are denoted by the operator , written before the symbol for aproperty, as recommended by IUPAC [82LAF]. An exception to this rule is the equilibriumconstant, cf. Section 2.1.6. The nature of the process is denoted by annotationof the , e.g., the Gibbs energy of formation, f G m , the enthalpy of sublimation, sub H m , etc. The abbreviations of chemical processes are summarised in Table 2.3.The most frequently used symbols for processes are f G and f H , the Gibbsenergy and the enthalpy of formation of a compound or complex from the elements intheir reference states (cf. Table 2.6).2.1.6 Equilibrium constantsThe IUPAC has not explicitly defined the symbols and terminology for equilibriumconstants of reactions in aqueous solution. The NEA has therefore adopted the conventionsthat have been used in the work Stability constants of metal ion complexes bySillén and Martell [64SIL/MAR, 71SIL/MAR]. An outline is given in the paragraphsbelow. Note that, for some simple reactions, there may be different correct ways toindex an equilibrium constant. It may sometimes be preferable to indicate the numberof the reaction the data refer to, especially in cases where several ligands are discussedthat might be confused. For example, for the equilibriumm M + q L Å M m L q (2.4)