Eisenhydroxidoxid

synthetischeA cold solution of 810 g of Fe(NO3)39H2O in two liters of water is poured slowly, with vigorous stirring, into an ammonia solution prepared by dissolving 120 g of gaseous NH3 in two liters of water (cooling necessary). The hydroxide which precipitates is amorphous to x-ray analysis. It is washed by stirring at least five times with eight-liter portions of cold water, each portion being decanted as completely as possible. The residual slurry is then stirred with sufficient cone. KOH solution to give a mixture approximately 2N and allowed to stand for 3-4 hours. Finally 100℃ steam is bubbled through for two hours. The precipitate is thereby transformed completely into bright-yellow α-FeO(OH), which shows a crystalline x-ray diffraction pattern.