Gold
hideGold (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.
For more information about Gold, read the full article at
Wikipedia.
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News tagged with gold
Single-Molecule Magnets Open New Door for Information Technology
Mar 09, 2009 |
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(PhysOrg.com) -- Recent research by scientists in Italy and France shows that that single molecules have the ability to store information via their magnetic state. Their work is a first step toward a new generation ...
Gene Testing In the Doctors Office
Nanotechnology / Bio & Medicine
Dec 02, 2009 |
5 / 5 (5) |
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(PhysOrg.com) -- A portable instrument manufactured by Nanosphere Inc. and recently approved by the FDA, can detect genetic variations in blood that alter the effectiveness of some drugs.
Fast, easy, and highly sensitive arsenic detection with gold nanoparticles
Nanotechnology / Nanomaterials
Nov 25, 2009 |
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(PhysOrg.com) -- Mention of arsenic poisoning usually brings to mind underhanded murder. However, the danger of arsenic poisoning from contaminated drinking water is far greater. Low concentrations of arsenic are found in ...
Harnessing nanopatterns: Tiny textures can produce big differences
Nanotechnology / Nanomaterials
Sep 24, 2009 |
5 / 5 (4) |
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(PhysOrg.com) -- Research at MIT has uncovered new information about how nanoscale patterns on the surface of a material can produce significant changes in the way it interacts with liquids. The discovery ...
Graphene Used As Floating-Molecular Carpet To Ornament It With 24-Carat Gold 'Snowflakes'
Nanotechnology / Nanomaterials
Oct 12, 2009 |
4.2 / 5 (6) |
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(PhysOrg.com) -- In an effort to make graphene more useful in electronics applications, Kansas State University engineers made a golden discovery -- gold "snowflakes" on graphene.
Gold solution for enhancing nanocrystal electrical conductance
Nanotechnology / Nanomaterials
Sep 10, 2009 |
5 / 5 (3) |
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In a development that holds much promise for the future of solar cells made from nanocrystals, and the use of solar energy to produce clean and renewable liquid transportation fuels, researchers with the U.S. ...
Oxygen in place of chlorine: Towards a more environmentally friendly propylene oxide synthesis
Nanotechnology / Nanomaterials
Oct 01, 2009 |
4.8 / 5 (4) |
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(PhysOrg.com) -- Propylene oxide is an important bulk chemical that is used primarily in the production of polyurethane plastics. Currently, propylene oxide is usually made from propylene (propene) in a process that uses ...
Fresh pot of tea strikes anti-cancer gold
Nanotechnology / Bio & Medicine
Mar 24, 2009 |
5 / 5 (10) |
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Researchers might one day brew up a cancer treatment in their afternoon cuppa, says a study in a Royal Society of Chemistry journal.
Housewife Remedy for Scurvy Preceded Medical Discovery
Mar 11, 2009 |
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(PhysOrg.com) -- A 100-page handwritten book by Mrs. Ebot Mitchell written in 1707 on household remedies contains among other things a recipe to treat scurvy. The recipe containing extracts from plants, orange ...
Targeting tumors using tiny gold particles
Nanotechnology / Bio & Medicine
May 04, 2009 |
5 / 5 (5) |
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(PhysOrg.com) -- It has long been known that heat is an effective weapon against tumor cells. However, it's difficult to heat patients' tumors without damaging nearby tissues.
Gold-palladium nanoparticles achieve greener, smarter production of hydrogen peroxide
Nanotechnology / Nanomaterials
Feb 19, 2009 |
4.3 / 5 (4) |
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Hydrogen peroxide is one of the world's most versatile and widely used chemicals. A powerful oxidizing agent, H2O2 is commonly used as a bleach, an antiseptic and a disinfectant.
Metal sheets with DNA framework may enable nanocircuits
Nanotechnology / Bio & Medicine
May 20, 2009 |
4.9 / 5 (8) |
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(PhysOrg.com) -- Using DNA not as a genetic material but as a structural support, Cornell researchers have created thin sheets of gold nanoparticles held together by strands of DNA. The work could prove useful ...
Researchers heat up gold to surprising effect: It gets harder not softer
Jan 22, 2009 |
4 / 5 (5) |
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Common sense tells us that when you heat something up it gets softer, but a team of researchers, led by University of Toronto chemistry and physics professor R.J. Dwayne Miller, has demonstrated the exact ...
Plugging in Molecular Wires
Feb 11, 2009 |
4.7 / 5 (3) |
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(PhysOrg.com) -- Plants, algae, and cyanobacteria (blue-green algae) are masters of everything to do with solar energy because they are able to almost completely transform captured sunlight into chemical energy. This is in ...
The gold standard: researchers use nanoparticles to make 3-D DNA nanotubes
Nanotechnology / Bio & Medicine
Jan 01, 2009 |
5 / 5 (8) |
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Arizona State University researchers Hao Yan and Yan Liu imagine and assemble intricate structures on a scale almost unfathomably small. Their medium is the double-helical DNA molecule, a versatile building ...
