Chuyên Đề Iron

Introduction Iron is the second most commonly used metal after aluminum despite its most abundant nature. On the surface of the earth, iron occurs both in native (uncombined) form in very limited quantities and with other elements aplenty as its ores. By contrast, owing to the poor solubility (2.3 Â 10À8 mol LÀ1 or 1.3 Â 10À3 mg LÀ1) of iron oxides in water, iron is found only in limited amounts in the oceans as its hydrates, namely, [Fe(OH)2] þ and [Fe(OH)4]À.