Science / Periodic Table of Elements / Iron (Fe): Atomic number: 26, Atomic mass: 55.85 g.mol -1, Electronegativity: 1.8, Density: 7.8 g.cm-3 at 20°C, Melting point: 1536 °C, Boiling point: 2861 °C, Vanderwaalsradius: 0.126 nm, Ionic radius: 0.076 nm (+2) ; 0.064 nm (+3), Isotopes: 8, Electronic shell: [ Ar ] 3d6 4s2, Energy of first ionisation: 761 kJ.mol -1, Energy of second ionisation: 1556.5 kJ.mol -1, Energy of third ionisation: 2951 kJ.mol -1, Standard potential: - o.44 V (Fe2+/ Fe ) ; 0.77 V ( Fe3+/ Fe2+ ), Discovered by: The ancients. Iron is a lustrous, ductile, malleable, silver-gray metal (group VIII of the periodic table). It is known to exist in four distinct crystalline forms. Iron rusts in dump air, but not in dry air. It dissolves readily in dilute acids. Iron is chemically active and forms two major series of chemical compounds, the bivalent iron (II), or ferrous, compounds and the trivalent iron (III), or ferric, compounds. Applications: Iron is the most used of all the metals, including 95 % of all the metal tonnage produced worldwide. Thanks to the combination of low cost and high strength it is indispensable. Its applications go from food containers to family cars, from scredrivers to washing machines, from cargo ships to paper staples. Steel is the best known alloy of iron, and some of the forms that iron takes include: pig iron, cast iron, carbon steel, wrought iron, alloy steels, iron oxides. Iron in the environment: Iron is believed to be the tenth most abundant element in the universe. Iron is also the most abundant (by mass, 34.6%) element making up the Earth; the concentration of iron in the various layers of the Earth ranges from high at the inner core to about 5% in the outer crust. Most of this iron is found in various iron oxides, such as the minerals hematite, magnetite, and taconite. The earth's core is believed to consist largely of a metallic iron-nickel alloy. Iron is essential to almost living things, from micro-organisms to humans. World production of new iron is over 500 million tonnes a year, and recycled iron add other 300 million tonnes. Economically workable reserves of iron ores exceed 100 billion tonnes. The main mining areas are China, Brazil, Australia, Russia and Ukraine, with sizeable amounts mined in the USA, Canada, Venezuela, Sweeden and India.
Science / Geology / Iron Formation: A layered deposit of chemical sedimentary rocks containing at least 15 percent (by weight) iron in the form of sulfide, oxide, hydroxide, or carbonate minerals. MORE