Metal complexes involving the heavier donor atoms. Part III. Stability of complexes of urea, semicarbazide, and their sulphur and selenium analogues with zinc, cadmium, and mercuric ions and the heats of formation of the mercuric complexes

Abstract

The basicity constants and heats of protonation of the ligands selenourea, semicarbazide, thiosemicarbazide, and selenosemicarbazide have been determined. The stability constants of complexes of urea, semicarbazide, and their sulphur and selenium analogues with zinc, cadmium, and mercuric ions have been measured by the metal electrode method and the heats of formation of the mercuric complexes by calorimetry. The relative donor properties of oxygen, sulphur, and selenium are compared.