Correlations between pairs of simple physicochemical parameters of metal ions and acute toxicity in mice.

Our earlier study of correlations between single physical parameters characterizing divalent metal ions and their acute toxicity in mice is extended to linear combinations of pairs of parameters chosen from among the following five: ionic radius, sum of ionization potentials, atomic weight, Williams softness parameter, and electronegativity. Some improvements in the correlations are found by employing a two-parameter fit to a given set of toxicity data. Similar results are obtained when the grouping of metal ions is based on criteria suggested by Kaiser.