On the Auger parameter of Cu(II) compounds

The Auger parameter (AP) of Cu(I) halides follow the trend: α ′ Cu(s) > α ′ CuI > α ′ CuBr > α ′ CuCl > > α ′ Cu(g) , in agreement with the electronic polarizabilities of the nearest‐neighbor ligands of the core‐ionized Cu(I) ion. On the contrary, the AP of Cu(II) halides and other Cu(II) compounds are close to that of copper metal. We extend our simple AP semiempirical model, published in this journal in 2019, to try to understand the unusual results reported for the Cu(II) compounds.