ON STATE OF MERCURY(2) TRACES IN AQUEOUS SOLUTIONS - COLLOIDAL BEHAVIOUR OF MERCURY

The state of radioactively labelled traces of bivalent mercury (3·10-8 and 10-6 moles/l) in aqueous solutions was studied by the method of centrifugation, ultrafiltration, dialysis and electromigration. In the nitrate solutions which have not been specially purified from chlorides and have pH values 0-2 the trace mercury exists in the form of molecular HgCl2. At higher pH values hydrolysis of mercury occurs so that molecular mercury (II) hydroxide is the main mercury species in the freshly prepared solutions with pH 4-13. Pseudocolloidal particles of mercury are formed in the aged solutions at pH 2-7 and 12-14, probably due to the adsorption of mercury on and/or the coprecipitation with foreign impurities in the solution. © 1969.