ELECTRON PAIRING AND CHEMICAL-BONDS - CHEMICAL-STRUCTURE, VALENCES AND STRUCTURAL SIMILARITIES FROM THE ANALYSIS OF THE FERMI HOLES

A new method of visualisation of bonding in molecules is introduced. T he method is based on the analysis of Fermi holes associated with cond itional probabilities of finding one electron of the pair provided the second, reference, electron is localised in a certain molecular regio n. Based on this analysis it is possible to get a clear and highly vis ual insight into the structure of molecular fragments (functional grou ps) in molecules. In addition to this visualisation, the new approach opens the possibility of the new definition of atomic and group valenc e and, also, can be applied as a new means of the quantitative charact erisation of similarity of structural fragments in the series of relat ed molecules.