Electron Affinity, Electronegativity, and Electrophilicity of Atoms and Ions

The electron affinity, electronegativity, and electrophilicity of several neutral atoms and their positive and negative ions are calculated at various levels of theory using different basis sets in the gas phase as well as in the presence of solvent and counterions. The electron affinity and electronegativity of all of the anions and dianions are negative in gas phase, and accordingly the electrophilicity is unexpectedly large vis-a-vis its quadratic definition. Many of these trends get altered in case the effects of solvent and counterions are taken into account.