Metal complexes involving the heavier donor atoms. Part V. Stability and heats of formation of silver(I), cadmium(II), and lead(II) complexes of semicarbazide, thiosemicarbazide, and selenosemicarbazide

Abstract

Stability constants of complexes of silver(I) with semicarbazide (sc), thiosemicarbazide (tsc), and selenosemicarbazide (ssc) have been measured by a metal-electrode method and those of cadmium(II) and lead(II) by a polarographic method. The heats of formation of these complexes have been measured calorimetrically. The free energy and enthalpy of formation of the silver(I) complexes follow the normal class ‘b’ donor-atom sequence O S < Se. For cadmium(II) and lead(II), although the general affinity order is similar, there are exceptions.