The paper gives the result of a bench scale mechanistic studies of mercury/sorbent reaction that showed that mercuric chloride (HgCl2) is readily adsorbed by alkaline earth and alkaline earth metal sorbents, which offers a less expensive alternative to the use of activated carbon. A laboratory scale, fixed bed apparatus was used to study the effects of sorbent properties on HgCl2 capture at 60, 100, and 140 C. Surface area, porosity, particle size, pore dia, and chemical surface basicity were analyzed for 11 sorbents. The reactivity of the sorbents is proposed to involve the formation of undentate and/or bidentate complexes on acidic and basic surface sites. Surface basicity alone is insufficient measure of sorbent capacity, supporting a theory that the acidic character of the surface is also important to the formation of the bidentate complex.