Search results
Results from the WOW.Com Content Network
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). Well-formed crystals are sought by collectors and are occasionally fashioned into gemstones when suitably free of flaws.
The name tungsten (which means ' heavy stone ' in Swedish and was the old Swedish name for the mineral scheelite and other minerals of similar density) is used in English, French, and many other languages as the name of the element, but wolfram (or volfram) is used in most European (especially Germanic and Slavic) languages and is derived from ...
An example of the tetragonal crystals, wulfenite Two different views (top down and from the side) of the unit cell of tP30-CrFe (σ-phase Frank–Kasper structure) that show its different side lengths, making this structure a member of the tetragonal crystal system.
Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is found in quartz veins and pegmatites associated with granitic intrusives. [5] Associated minerals include cassiterite, scheelite, bismuth, quartz, pyrite, galena, sphalerite, and arsenopyrite.
The Gladstone–Dale relation [1] is a mathematical relation used for optical analysis of liquids, the determination of composition from optical measurements. It can also be used to calculate the density of a liquid for use in fluid dynamics (e.g., flow visualization [2]).
Scheelite is treated similarly using sodium carbonate. Sodium tungstate can also be produced by treating tungsten carbide with a mixture of sodium nitrate and sodium hydroxide in a fusion process which overcomes the high exothermicity of the reaction involved. Several polymorphs of sodium tungstate are known, three at only one atmosphere ...
Internal rotation stretch. Holding a towel or resistance band, lift your unaffected arm above your head. Slowly reach back with your frozen arm and grab the end of the band or towel.
New York: The International Nickel Company, Inc., 1941: 16. — "Values ranging from 21.3 to 21.5 gm/cm 3 at 20 °C have been reported for the density of annealed platinum; the best value being about 21.45 gm/cm 3 at 20 °C." 21.46 g/cm 3 — Rose, T. Kirke. The Precious Metals, Comprising Gold, Silver and Platinum. New York: D. Van Nostrand ...