iron

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Hard, malleable and ductile, silver-grey, metallic element, atomic number 26, relative atomic mass 55.847. It chemical symbol comes from the Latin ferrum. It is the fourth most abundant element in the Earth's crust. Iron occurs in concentrated deposits as the ores haematite (Fe₂O₃), spathic ore (FeCO₃), and magnetite (Fe₃O₄). It sometimes occurs as a free metal, occasionally as fragments of iron or iron–nickel meteorites.

Iron is extracted from iron ore in a blast furnace. The chemical reactions of iron with oxygen, water, acids, and other substances, can be explained by its position in the middle of the reactivity series of metals. Iron is the most useful of all metals; it is strongly magnetic and is the basis for steel (an alloy with carbon and other elements) and cast iron. Steel is used for buildings, bridges, ships, car bodies, and tools. Stainless steel is used for car parts, kitchen sinks, and cutlery. In electrical equipment iron is used in permanent magnets and electromagnets, and forms the cores of transformers and magnetic amplifiers. The corrosion of iron is called rusting and is an example of an oxidation reaction. In the human body, iron is an essential component of haemoglobin, the molecule in red blood cells that transports oxygen to all parts of the body. A deficiency in the diet causes a form of anaemia.

Known as ‘white sun in blue sky’, the flag of Chinese revolutionary leader Sun Zhong Shan appears in the canton. The rays of the sun represent 12 traditional Chinese hours (each equalling two hours) symbolizing progress. Red is a traditional Chinese colour. Effective date: 8 October 1928. >>