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Cast Iron
Iron (IPA: /ˈaɪə(ɹ)n/) is a chemical element with the symbol Fe (Latin: ferrum) and atomic number 26. Iron is a group 8 and period 4 metal. more...
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Iron and nickel are notable for being the final elements produced by stellar nucleosynthesis, and thus the heaviest elements which do not require a supernova or similarly cataclysmic event for formation. Iron and nickel are therefore the most abundant metals in metallic meteorites and in the dense-metal cores of planets such as Earth.
Characteristics
Iron is believed to be the tenth most abundant element in the universe. The concentration of iron in the various layers in the structure of the Earth ranges from high (probably greater than 80%, perhaps even a nearly pure iron crystal) at the inner core, to only 5% in the outer crust. Iron is second in abundance to aluminium among the metals and fourth in abundance in the crust. Iron is the most abundant element by mass of our entire planet, making up 35% of the mass of the Earth as a whole.
Iron is a metal extracted from iron ore, and is almost never found in the free elemental state. In order to obtain elemental iron, the impurities must be removed by chemical reduction. Iron is the main component of steel, and it is used in the production of alloys or solid solutions of various metals, as well as some non-metals, particularly carbon. The many iron-carbon allotropes, which have very different properties, are discussed in the article on steel.
Nuclei of iron have some of the highest binding energies per nucleon, surpassed only by the nickel isotope 62Ni. The universally most abundant of the highly stable nuclides is, however, 56Fe. This is formed by nuclear fusion in stars. Although a further tiny energy gain could be extracted by synthesizing 62Ni, conditions in stars are unsuitable for this process to be favoured, and iron abundance on Earth greatly favors iron over nickel, and also presumably in supernova element production. When a very large star contracts at the end of its life, internal pressure and temperature rise, allowing the star to produce progressively heavier elements, despite these being less stable than the elements around mass number 60, known as the "iron group". This leads to a supernova.
Some cosmological models with an open universe predict that there will be a phase where as a result of slow fusion and fission reactions, everything will become iron.
Iron (as Fe2+, ferrous ion) is a necessary trace element used by all known living organisms. Iron-containing enzymes, usually containing heme prosthetic groups, participate in catalysis of oxidation reactions in biology, and in transport of a number of soluble gases. See hemoglobin, cytochrome, and catalase.
Read more at Wikipedia.org
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