On the bonding of the ions PO43-, SO42-, ClO4-, ClO3-and CO32-as studied by X-ray spectroscopy andab initioSCF-MO calculations

Abstract
The ionization energies of the valence electrons of the ions PO4 3-, SO4 2-, ClO4 -, ClO3 - and CO3 2- are measured by X-ray photoelectron spectroscopy. An assignment of the spectra is made using the results of all electron ab initio SCF-MO calculations, reported here, together with X-ray emission spectra from the literature. The calculated atomic orbital composition of the molecular orbitals allows the intensities of the X-ray spectra to be understood, and provides further evidence for d-orbital participation in the bonding of the second row atoms.