Recently, it has been found that monodisperse pseudocubic hematite particles 1.65 mum in mean edge length can be obtained in large quantities of the order of the molality with a yield close to 100%, by adding 100 ml of 5.4 N NaOH to 100 ml of well-stirred 2.0 M FeCl3 and aging the resulting condensed gel of Fe(OH)3 for 8 days at 100-degrees-C. The method was provisionally referred to as the gel-sol method. As an application of this technique, when 90 ml of 6.0 N NaOH and 10 ml of sulfate or phosphate solution were added instead of 100 ml of 5.4 N NaOH, the pseudocubic particles turned into peanut-type particles via an ellipsoidal shape with increasing concentration of the additives.
