Abstract
A separation of the effects of substituent groups into distinct σ and π contributions and the influence of the σ and π contributions on Hamiltonians and wave functions of various cores has proved useful for describing several diverse phenomena in N–F compounds. (1) The ``anomalous'' difference in bond strengths in NF3 and NF2 where the N–F bond in NF3 is weaker than that in NF2. (2) The nonconstancy of the δK value for F in ionization potentials of NF3 and CF3, whereas other substituent group effects were constant. (3) The similarity between the effect of F on ionization potentials of NF2 and of CF3.