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Tungsten (also called wolfram) [ 11][ 12] is a chemical element; it has symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolated as a metal in 1783.
Iridium is a chemical element; it has symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of 22.56 g/cm 3 (0.815 lb/cu in) [8] as defined by experimental X-ray crystallography. [a] 191 Ir and 193 Ir ...
Tungsten is one of the oldest elements used for alloying steel. It forms a very hard carbide and iron tungstite. High tungsten content in the alloy, however, tends to cause brittleness and makes it subject to fracturing rather than bending. [1] The SAE designation for all tungsten steels consist of four numbers beginning with the number 7, in ...
Occasionally fluoresces red under mid-wave UV. Scheelite is a calcium tungstate mineral with the chemical formula Ca W O 4. It is an important ore of tungsten (wolfram). Scheelite is originally named after Swedish chemist Carl Wilhelm Scheele (1742–1786).
Wolframite is an iron, manganese, and tungstate mineral with a chemical formula of (Fe,Mn)WO4 that is the intermediate mineral between ferberite ( Fe2+ rich) and hübnerite ( Mn2+ rich). [4] Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is found in quartz veins and pegmatites associated ...
Rhodium is a chemical element; it has symbol Rh and atomic number 45. It is a very rare, silvery-white, hard, corrosion-resistant transition metal. It is a noble metal and a member of the platinum group. It has only one naturally occurring isotope, which is 103 Rh. Naturally occurring rhodium is usually found as a free metal or as an alloy with ...
Uranium is a chemical element; it has symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactively decays, usually by emitting an alpha particle.
Tungsten (IV) oxide is the chemical compound with the formula W O 2. The bronze-colored solid crystallizes in a monoclinic cell. [1] The rutile -like structure features distorted octahedral WO 6 centers with alternate short W–W bonds (248 pm). [1] Each tungsten center has the d 2 configuration, which gives the material a high electrical ...