The correlation between molecular structure and tendency to maintain or to destroy iron passivity in aqueous solutions—i. The electrostatic hypothesis

The electrostatic hypothesis of Cartledge relates the internal charge distribution of anions of the form XO 4 n− to their ability to maintain or to destroy passivity. Application of the hypothesis to other species is considered here. Certain soluble compounds, e.g. carboxylic acid salts, appear to conform. However there are some contradictions. Some of these are explained by hydrogen bonding, as with fluorine-containing compounds. With certain nitrogen-containing passivity stabilisers, in order to fit their behaviour to the hypothesis, rearrangement of an electron lone pair is postulated to occur when the compound adsorbs at the passive surface.