To the best of my knowledge, the mercury substitutes into the crystalline structure of the external surface of the aluminum, forming an alloy. I may be incorrect, but I believe that this alloy has a higher reduction potential than aluminum, making it less reactive. Mercury is used for the same purpose when sodium is used as the reducing metal. Without the decrease in reactivity provided by the mercury, the aluminum would readily react with the solvent to form hydrogen gas at certain pH levels. Other than that, I don't really know much about the role of the mercury. Does the mercury remove the initial layer of Al2O3 or does the decrease in pH produced by the mercury salt remove it? Does the surface of the aluminum become saturated with mercury at a certain surface concentration? If so, is this saturation usually reached while amalgamating? Is it better to have more or less mercury concentration on the surface? Does a higher surface concentration of mercury decrease the reaction rate of the aluminum with the solvent? the nitromethane and ketone? Do the electrons donated to the nitro/ketone come from the aluminum atoms or the mercury atoms? Does this electron transfer proceed by a free radical mechanism, or do the reactant coordinate to the metal surface? I'm sure that most of these questions cannot be answered here, but I have been trying to research the mechanism of this reaction in the library and have found nothing written in English. I did find an article on the reaction mechanism in either French or German. Can anybody translate this?