Human rights treaties benefit the world's most oppressed

International human rights treaties really do work, and they work most effectively against the most repressive governments, argues Emily Hencken Ritter, associate professor of political science, in a new book called Contentious ...

Making metal with the lightness of air

Gold, silver and copper are heavy metals, but LLNL scientists can now make them nearly as light as air—in a form so tiny it can ride on a mosquito's back.

Gold-coated fungi are the new gold diggers

The thread-like fungi attach gold to their strands by dissolving and precipitating particles from their surroundings, in a process that could offer clues for finding new gold deposits.

Scientists proposed a novel configuration of nanoscopes

Scientists from Tomsk Polytechnic University together with colleagues proposed using special diffraction gratings with gold plates instead of microlenses used in the classic configuration to obtain images in nanoscopes. Microlenses ...

New Flatland material: Physicists obtain quasi-2D gold

Researchers from the MIPT Center for Photonics and 2-D Materials have synthesized a quasi-2-D gold film, revealing how materials not usually classified as two-dimensional can form atomically thin layers. Published in Advanced ...

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Gold

Gold (pronounced /ˈɡoʊld/) is a chemical element with the symbol Au (Latin: aurum) and an atomic number of 79. It has been a highly sought-after precious metal in jewelry, in sculpture, and for ornamentation since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is dense, soft, shiny and the most malleable and ductile pure metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. It is one of the coinage metals and formed the basis for the gold standard used before the collapse of the Bretton Woods system in 1971.

At the end of 2006, it was estimated that all the gold ever mined totaled 158,000 tonnes. This can be represented by a cube with an edge length of just 20.2 meters. Modern industrial uses include dentistry and electronics, where gold has traditionally found use because of its good resistance to oxidative corrosion and excellent quality as a conductor of electricity. Chemically, gold is a transition metal and can form trivalent and univalent cations upon solvation. At STP it is attacked by aqua regia (a mixture of acids), forming chloroauric acid and by alkaline solutions of cyanide but not by single acids such as hydrochloric, nitric or sulfuric acids. Gold dissolves in mercury, forming amalgam alloys, but does not react with it. Since gold is insoluble in nitric acid which will dissolve silver and base metals, this is exploited as the basis of the gold refining technique known as "inquartation and parting". Nitric acid has long been used to confirm the presence of gold in items, and this is the origin of the colloquial term "acid test", referring to a gold standard test for genuine value.

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