Nickel (Ni)

Science / Periodic Table of Elements / Nickel (Ni): Atomic number: 28, Atomic mass: 58.71 g.mol -1, Electronegativity: 1.8, Density: 8.9 g.cm-3 at 20°C, Melting point: 1453 °C, Boiling point: 2913 °C, Vanderwaals radius: 0.124 nm, Ionic radius: 0.069 nm (+2) ; 0.06 nm (+3), Isotopes: 10, Electronic shell: [ Ar ] 3d8 4s2, Energy of first ionisation: 735 kJ.mol -1, Energy of second ionisation: 1753 kJ.mol -1, Energy of third ionisation: 3387 kJ.mol -1, Standard potential: - 0.25 V, Discovered by: Alex Constedt 1751. Nickel is silvery-white. hard, malleable, and ductile metal. It is of the iron group and it takes on a high polish. It is a fairly good conductor of heat and electricity. In its familiar compounds nickel is bivalent, although it assumes other valences. It also forms a number of complex compounds. Most nickel compounds are blue or green. Nickel dissolves slowly in dilute acids but, like iron, becomes passive when treated with nitric acid. Finely divided nickel adsorbs hydrogen. Applications: The major use of nickel is in the preparation of alloys. Nickel alloys are characterized by strength, ductility, and resistance to corrosion and heat. About 65 % of the nickel consumed in the Western World is used to make stainless steel, whose composition can vary but is tipycally iron with aroun 18% chromium and 8% nichel. 12 % of all the nichel consumed goes into superalloys. The remaining 23% of consumption is divided between alloy steels, rechargeable batteries, catalysts and other chemicals, coinage, foundry products, and plating. Nickel is easy to work and can be drawn into wire. It resist corrosion even at high temperatures and for this reason it is used in gas turbines and rocket engines. Monel is an alloy of nickel and copper (e.g. 70% nichel, 30% copper with traces of iron, manganese and silicon), which is not only hard but can resist corrosion by sea water, so that it is ideal for propeller shaft in boats and desalination plants. Nickel in the environment: Most nichel on Earth is inacessible because it is locked away in the planet's iron-nickel molten core, which is 10 % nickel. The total amount of nickel dissolved in the sea has been calculated to be around 8 billion tonnes. Organic matter has a strong ability to absorb the metal which is why coal and oil contain considerable amounts. The nichel content in soil can be as low as 0.2 ppm or as high as 450 ppm in some clay and loamy soils. The average is around 20 ppm. Nickel occurs in some beans where it is an essential component of some enzymes. Another relatively rich source of nickel is tea which has 7.6 mg/kg of dried leaves. Nickel occurs combined with sulphur in millerite, with arsenic in the mineral niccolite, and with arsenic and sulphur in nickel glance. Most ores from which nichel is extracted are iron-nickel sulphides, such as pentlandite. The metal is mined in Russia, Australia, New caledonia, Cuba, Canada and South Africa. Annula production exceeds 500.000 tonnes and easily workable reserves will last at least 150 years.

Nickel Metal Hydride Battery (NiMH)

Technology / Cell Phones / Nickel Metal Hydride Battery (NiMH): A rechargeable battery that is capable of holding more power that a NiCd battery and suffers much less from memory effect. It is also typically more expensive than a NiCd battery. MORE

Nickel Metal-Hybrid (NiMH)

Technology / Digital Cameras / Nickel Metal-Hybrid (NiMH): A type of rechargeable battery that can be recharged many times. Nimh batteries provide sufficient power to run digital cameras and flashes. MORE

Nickel Defense

Entertainment / Football / Nickel Defense: When a defense brings in a 5th defensive back to replace a linebacker on the field, increasing its pass coverage. MORE

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