Recent advances in the mechanistic understanding of mercury oxidation on a carbon surface in flue gas are reviewed in this paper. Theoretical calculations were performed to determine whether the energetics are feasible for a proposed detailed model for oxidative addition of elemental mercury on a carbon edge structure. The results of the calculation show that mercury complexation with a carbenium ion formed at a zigzag edge carbon has a small positive Delta G. but attack of chloride on the complex will proceed with negative AG. The energetics rule out a direct covalent bond formation between mercury and the carbenium ion. Alternative concerted reaction models and double-charged models for the mechanism are also feasible but have not yet been computed. (C) 2009 Elsevier B.V. All rights reserved.