Use
3-(Hydroxymercuri)-4-nitro-o-cresol inner salt (Metaphen)occurs as a yellow powder that is practically insoluble in water and is sparingly soluble in alcohol and most organicsolvents. The sodium salt probably has the “inner salt”structure in which the inner shell electrons of mercury areoccupied. The bonding to mercury in this salt should becollinear, thus the following structure is somewhat improbable.Nevertheless, this structure is shown in the USP andthe Merck Index.Nitromersol is nonirritating to mucous membranes and isnonstaining. Therefore, at one time, it was a very popularantiseptic for skin and ocular infections. Nitromersol haslargely been replaced by superior agents.