Morphology of barium sulfate synthesized with barium(II)–aminocarboxylate chelating precursors

The morphology of barium sulfate (BaSO4), synthesized using the hydrothermal reaction of BaII–aminocarboxylate chelating precursors, was investigated. The precursors ethylenediaminetetraacetic acid (EDTA), bis(2-aminoethyl)ethyleneglycoltetraacetic acid (EGTA) and nitrilotriacetic acid (NTA) were dissolved by heating, resulting in the formation of BaSO4 with rod-like, rhombohedral and spindle-shaped morphologies, respectively. Changing the chelating reagent resulted in the formation of BaSO4 with differing morphologies. There was a correlation between the morphology of BaSO4 and the dissociation constant of the BaII–aminocarboxylic acid complexes. When the dissociation constant was small, BaSO4 formed rhombohedral morphologies, when it was large, spindle-shaped morphologies were formed. N 1s XPS measurements indicated that the aminocarboxylic acid was adsorbed on the surface of the precipitated particles. Comparison of the peak intensity X-ray diffraction patterns of EDTA and EGTA showed growth of the {101} face when EDTA was used.