Ionization energies and electronic structure of N3P3Cl6 as determined by UV photoelectron spectroscopy and the Xα scattered wave method

Ionization energies have been measured for N₃P₃Cl₆ by He I photoelectron spectroscopy and they are compared with values calculated with the overlapping-spheres version of the Xα scattered wave method; the average discrepancy is less than 0.4 eV. The wavefunctions and associated charge distributions are used for assessing models of ring π bonding, and comparisons are made with previous calculations for N₃P₃F₆ and N₄P₄F₈. The calculated charge distributions are related to trends in measured core electron binding energies, and have important implications for the interpretation of Faraday effect measurements on cyclic phosphazenes.