Ferric Oxide: Hydroxide Precipitated from Ferric Chloride with Ammonia, Then Heated

Ferric oxide, Fe2O3, made by way of the hydroxide as Thorpe's Dictionary (1912) gives it. Ferric chloride solution with excess ammonia throws down a bulky, brown, slimy hydroxide, which shrinks a great deal as it dries. Heated, it slowly gives up its water at 320 °C; taken to dull redness it suddenly contracts and glows, and is then much less soluble in acids. The picture: our diagram.