HGI2/I- EQUILIBRIUM IN SOLVENT 96 PERCENT METHANOL/4 PERCENT WATER - A SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF INORGANIC MERCURY(2)

The third stepwise stability constant for the Hg2+/I- system has been found to be 7·4 × 104 1 mole-1 in solvent 96% methanol/4% water, and the molar absorptivities of HgI2 and HgI3 - in this solvent, at several wavelengths, are reported. Inorganic mercury(II) may be determined very conveniently, as the species HgI3 -, by absorbance measurements on solutions of 2·5 × 10-3 M potassium iodide in 96% methanol/4% water, containing 10-4 to 10-5 M inorganic mercury(II). © 1968.