Nucleation studies in supersaturated aqueous solutions of urea and urea nitrate doped with organic dopants

Induction periods have been measured for various supersaturated aqueous sol utions of urea doped with urea nitrate and urea oxalate separately and urea nitrate doped with thiourea and urea oxalate separately by the direct visi on method. Nucleation is promoted by both the dopants in the case of urea. In the case of urea nitrate thiourea doping promoted nucleation while urea oxalate doping inhibited it. The critical nucleation parameters increase wi th increase in doping concentration of the urea solutions and thiourea dopi ng concentration of the urea nitrate solutions while they decrease with the increase in concentration of urea oxalate doping in the urea nitrate solut ions.