A simple method for studying the formation of calcium oxalate

The nucleation and crystal growth of calcium oxalate were studied under different conditions using a nephelometer to measure the turbidities of suspensions produced when dilute solutions of calcium chloride dihydrate and sodium oxalate were mixed. The amount of material produced was less when calcium was in excess of oxalate than vice versa. For equimolar amounts of the precipitating reagents the rate of formation of calcium oxalate was rapid when calcium and oxalate concentrations were 1-25 mmol/l. but slow when they were 0-5mmol/l. Sodium citrate and heparin inhibited nucleation and crystal growth and at certain concentrations prevented nucleation for the duration of the experiment. The method is simple and quick and requires only a small amount of material.