Metallothermic reduction as an electronically mediated reaction

The commonly held view that metallothermic reduction is strictly a chemical reaction and that the process is rate limited by mass transfer has been fo und to be incomplete. In a study of the production of tantalum powder by th e reaction of K2TaF7 with sodium, it has been shown that there are two domi nant kinetic pathways, both involving electron transfer. Furthermore, the o verall rate of reaction is limited by electron transport between the reacta nts, This indicates that metallothermic reduction is an "electronically med iated reaction" (EMR). Experiments found that the location of the tantalum deposit and its morphology are governed by the reaction pathway.