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Tungsten (also called wolfram) [14] [15] is a chemical element; it has symbol W and atomic number 74. It is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a distinct element in 1781 and first isolated as a metal in 1783.
The authors examined cross sections of the shards for 31 trace elements using mass spectrometry by converting sample molecules into charged ions.While there was plenty of the expected elements on ...
Tungsten is mainly found in the minerals wolframite and scheelite, and it usually never occurs as a free element in nature. The largest producers of tungsten in the world are China, Russia, and Portugal. Seaborgium is a transuranium element that is made artificially by bombarding californium-249 with oxygen-18 nuclei. It is artificial ...
A table listing the 17 rare-earth elements, their atomic number and symbol, the etymology of their names, and their main uses (see also Applications of lanthanides) is provided here. Some of the rare-earth elements are named after the scientists who discovered them, or elucidated their elemental properties, and some after the geographical ...
Tungsten was discovered in 1781 by Swedish chemist Carl Wilhelm Scheele. Tungsten has the highest melting point of all metals, at 3,410 °C (6,170 °F). Filament of a 200 watt incandescent lightbulb highly magnified. Up to 22% Rhenium is alloyed with tungsten to improve its high temperature strength and corrosion resistance.
Another catalytic use of tungsten is as a De-NO X catalyst which is used in the treatment of nitrogen oxide emissions to convert harmful nitrogen oxides into inert N 2 gas. [14] Another modern day use of tungsten is as a lubricant. Tungsten disulfide (WS 2) is a lubricant with a dynamic coefficient of friction of ~0.03. Tungsten disulfide can ...
Tin is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO 2. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4.
The periodic table and law are now a central and indispensable part of modern chemistry. The periodic table continues to evolve with the progress of science. In nature, only elements up to atomic number 94 exist; [a] to go further, it was necessary to synthesize new elements in the laboratory.