Nucleation studies and crystal growth of (NH 4)H 2PO 4 doped with thiourea in supersaturated aqueous solutions

Department of Chemical Engineering, National Taiwan University, T’ai-pei, Taipei, Taiwan
Materials Chemistry and Physics (Impact Factor: 2.13). 08/2002; 76(2):181-186. DOI: 10.1016/S0254-0584(01)00525-9

ABSTRACT The metastable zone width studies were carried out for various temperatures for supersaturated aqueous solutions of ammonium dihydrogen orthophosphate added with 1mol% of thiourea. The metastable zone width is increased with the addition of thiourea. The induction period was studied and various critical nucleation parameters were calculated based on the classical theory for homogeneous crystal nucleation. The induction period is increased with the increase of thiourea addition. The critical nucleation parameters vary with increase in doping concentration. The results are reported and discussed. The crystals were grown for various doping concentrations of thiourea and the morphological changes are discussed.

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