Electron-pairing energy

Crystal field splitting energy compared to the electron pairing energy. 

While the first electrochemical reduction potential provides an estimate for Ac (assuming it is a reversible process), the second and higher reduction potentials do not provide the spectrum of single electron affinity levels. Rather, they provide information about two-electron, three-electron, and higher electron reduction processes, and, therefore, depend on electron pairing energy. Thus, the utility of solution-phase reduction potentials for estimating solid-state affinity levels is... 

These two contributions represent the value of the one-electron integral /(Is) multiplied by two because there are two electrons in the ls-orbital, and the electron-pair energy (Is Is) between these electrons. Specifically, one has ... 

For a further discussion of this electron-pair energy (Is Is), one can introduce into equ. (7.56a) a hydrogenic Pu(r) radial function, and derive... 

Low-spin cations. The CFSE s for these cations are corrected for electron-pairing energies which approximate the A0 values. 

Crystal Field Splittings, Ao, and Mean Electron Pairing Energies, P, for Several Transition-metal Ions (energies in cm-1)... 

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