Organic dianion, dication

Of these four methods, only (i) has been seriously explored for organic metals methods (ii), (iii), and (iv) do not necessarily stabilize the dication/ dianion states. 

Since electrode measurements involve low substrate concentrations, reactive impurities have to be held to a very low level. The physical data and purification methods for several organic solvents used in electrode measurements have been summarized (Mann, 1969). But even when careful procedures for solvent and electrolyte purification are employed, residual impurities can have profound effects upon the electrode response. For example, the voltam-metric observation of dications (Hammerich and Parker, 1973, 1976) and dianions (Jensen and Parker, 1974, 1975a) of aromatic hydrocarbons has only been achieved during the last ten years. The stability of radical anions (Peover, 1967) and radical cations (Peover and White, 1967 Phelps et al., 1967 Marcoux et al., 1967) of aromatic compounds was demonstrated by cyclic voltammetry much earlier but the corresponding doubly charged ions were believed to be inherently unstable because of facile reactions with the solvents and supporting electrolytes. However, the effective removal of impurities from the electrolyte solutions extended the life-times of the dianions and dications so that reversible cyclic voltammograms could be observed at ambient temperatures even at very low sweep rates. 

Only the middle three compounds are common in organic chemistry. In the monocation and dication, there are one or two dative bonds respectively. The dication is very rare, while the dianion only commonly exists in inorganic compounds. Where the substituent in the neutral compound is an alkyl group, then the resultant compounds, namely ROH and R20, are called alcohols and ethers... 

These general formulae describe the ionic and neutral states of all the common species of oxygen compounds. The middle three species are the ones that are common in organic chemistry. The dianion commonly occurs in inorganic compounds as the ionic oxide. The dication is rare under all circumstances, since the high charge density upon the oxygen reduces its stability. 

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