The Negative Difference Effect and Unipositive Mg +

This paper evaluates current understanding of the negative difference effect (NDE) in the corrosion of magnesium. There is strong support for the existence of the unipositive magnesium ion and the unipositive Mg + ion NDE mechanism has been shown to be useful in providing a framework within which it is possible to evaluate the expected rate of production of Mg ++ and H 2 . However, the uncertainty concerning the existence of the unipositive Mg + ion means that there is scope for further research.