INFLUENCE OF PH ON THE MORPHOLOGY OF KBR SOLUTION GROWTH

The morphodrom of KBr crystal, growing in aqueous solution, has been o btained as a function of pH and supersaturation, by means of in situ o bservation with an optical microscope. The habit of the crystal change d from cubic to octahedral with increasing pH and supersaturation. The growth rate along [100] increased with increasing pH, while that alon g [111] decreased. The preferential adsorption of hydronium ions on th e {100} face and OH- ions on the {111} face, resulting in the restrict ion of the growth rates was proposed for the interpretation of the inf luence of pH on the change of crystal habit. In situ observation of th e macroscopic growth step patterns on the {100} face supported this pr esumption for the influence of pH on its growth.