The −1 oxidation state occurs in aurides, compounds containing the Au − anion. Caesium auride (CsAu), for example, crystallizes in the caesium chloride motif; [43] rubidium, potassium, and tetramethylammonium aurides are also known. [44] Gold has the highest electron affinity of any metal, at 222.8kJ/mol, making Au − a stable species, [45] analogous to the halides. Au, which decays by proton emission with a half-life of 30 µs. Most of gold's radioisotopes with atomic masses below 197 decay by some combination of proton emission, α decay, and β + decay. The exceptions are 195 Picture this: an induction furnace is like a wizard's cauldron. It uses something called "electromagnetic induction" to create heat. Think of it as a special magnet that talks to the gold, making it all warm and gooey. The gold goes from solid to liquid, just like butter on a hot summer day! Question 3: Can Electric Arc Furnaces Handle Gold Melting? Gold does not react with sulfur directly, [41] but gold(III) sulfide can be made by passing hydrogen sulfide through a dilute solution of gold(III) chloride or chlorauric acid.

Moors, Annelies (2013). "Wearing gold, owning gold: the multiple meanings of gold jewelry". Etnofoor. 25 (1): 78–89. ISSN 0921-5158. OCLC 858949147. Gold is mentioned in the Amarna letters numbered 19 [86] and 26 [87] from around the 14th century BC. [88] [89] In 2020, the world's largest gold producer was China, followed by Russia and Australia. [9] A total of around 201,296 tonnes of gold exists above ground, as of 2020 [update]. [10] This is equal to a cube with each side measuring roughly 21.7 meters (71ft). The world's consumption of new gold produced is about 50% in jewelry, 40% in investments, and 10% in industry. [11] Gold's high malleability, ductility, resistance to corrosion and most other chemical reactions, and conductivity of electricity have led to its continued use in corrosion-resistant electrical connectors in all types of computerized devices (its chief industrial use). Gold is also used in infrared shielding, the production of colored glass, gold leafing, and tooth restoration. Certain gold salts are still used as anti-inflammatories in medicine.

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The earliest recorded metal employed by humans appears to be gold, which can be found free or " native". Small amounts of natural gold have been found in Spanish caves used during the late Paleolithic period, c. 40,000 BC. [78] a b c La Niece, Susan (senior metallurgist in the British Museum Department of Conservation and Scientific Research) (15 December 2009). Gold. Harvard University Press. p.10. ISBN 978-0-674-03590-4 . Retrieved 10 April 2012.

about 1,943 degrees Fahrenheit). This makes melting gold extremely dangerous; raising the metal to such a high temperature, and then processing it, risks severe burns. Special equipment must also be used to hold the metal in its liquid form; typically a crucible and tongs made of a heat-resistant material are needed to handle these extreme temperatures. Pure metallic (elemental) gold is non-toxic and non-irritating when ingested [213] and is sometimes used as a food decoration in the form of gold leaf. [214] Metallic gold is also a component of the alcoholic drinks Goldschläger, Gold Strike, and Goldwasser. Metallic gold is approved as a food additive in the EU ( E175 in the Codex Alimentarius). Although the gold ion is toxic, the acceptance of metallic gold as a food additive is due to its relative chemical inertness, and resistance to being corroded or transformed into soluble salts (gold compounds) by any known chemical process which would be encountered in the human body.Characteristics Gold can be drawn into a monatomic wire, and then stretched more before it breaks. [12] A gold nugget of 5mm (0.20in) in size can be hammered into a gold foil of about 0.5m 2 (5.4sqft) in area. Gold can be used in food and has the E number 175. [201] In 2016, the European Food Safety Authority published an opinion on the re-evaluation of gold as a food additive. Concerns included the possible presence of minute amounts of gold nanoparticles in the food additive, and that gold nanoparticles have been shown to be genotoxic in mammalian cells in vitro. [202] The Ever Popular Krugerrand". americansilvereagletoday.com. 2010. Archived from the original on 3 February 2011 . Retrieved 30 August 2011. Earth's Gold Came from Colliding Dead Stars". David A. Aguilar & Christine Pulliam. cfa.harvard.edu. 17 July 2013 . Retrieved 18 February 2018.