We have used oxidation state differences between bound atoms and molecular orbital images in an attempt to interpret bonding in the species ONF3, OCF3- and FNO2. The calculated bond lengths in these molecules is not in accord with the Lewis structure models and in every case appears to suggest a valence at the central atom greater than four. We have used series of related molecules, ONF3 through ONH3; OCF3- through OCH3- and FNO2 through HNO2 to study the variation of bond lengths and to relate these to changes in ionic character as described by oxidation state differences. This has been combined with molecular orbital modeling to provide an understanding of the nature of bonding in these molecules.