Reaction of mercury ions in potassium halide lattices

Single crystals of potassium halides grown from the melt doped with Hg(II) halides contain mainly Hg(II), and only small amounts of the Hg(I) species formed by partial decomposition. When the alkalihalides are doped with Hg(I), species found in the KI crystal are mainly Hg(I); both Hg(I) and Hg(II) in KBr, but in KCl the monovalent mercury salt decomposes almost completely to its elements. The different species were identified by a study of the spectra of the doped single crystals, before and after additive coloration, and the spectra of the pure alkalihalides coated with the respective mercury halide at room temperature.