Synthesis of Monodisperse CdS and ZnS Particles from Concentrated Solutions of the EDTA–Metal Complexes

Abstract

Monodisperse CdS particles with mean diameter 0.51 μm having 3.33% coefficient of variation (relative standard deviation) in size distribution were obtained in large quantities by instantaneous addition of 5 ml of 1.2 mol dm−3thioacetamide (TAA) containing 1 wt% gelatin to 20 ml of Cd–EDTA solution consisting of 0.300 mol dm−3Cd(OH)2, 0.303 mol dm−3EDTA·2Na, 2.0 mol dm−3CH3COONH4, 0.6 mol dm−3NH3, and 1 wt% gelatin. After the addition of the TAA solution, the system was aged for 8 h at 60°C under agitation. The yield was 91.5%. Uniform ZnS particles of mean diameter 0.73 μm with a 4.08% coefficient of variation in size distribution were also obtained by analogous preparation procedures in which Zn(NO3)2was used in place of Cd(OH)2.