Pure Gold Definition Science
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Pure Gold Definition Science

In chemistry, gold is a transition metal and an element of group 11. It is one of the least reactive and solid chemical elements under normal conditions. Ancient Egyptian statuette of Amun; 945-715 BC; Gold; 175 mm × 47 mm (6.9 inches × 1.9 inches); Gold(II) compounds at the Metropolitan Museum of Art are generally diamagnetic with Au-Au bonds such as [Au(CH2)2P(C6H5)2]2Cl2. Evaporation of a solution of Au(OH)3 in concentrated H2SO4 produces red crystals of gold(II) sulphate, Au2(SO4)2. Originally considered a mixed valence compound, it has been shown to contain Au4+2 cations, analogous to the better-known mercury(I)Hg2+2 ion. [46] [47] A gold(II) complex, the tetraxenonogold(II) cation, which contains xenon as a ligand, occurs in [AuXe4](Sb2F11)2. [48] It is estimated that up to a quarter of the world`s annual gold production comes from artisanal or small-scale mining. [120] [121] [122] European research on America has been informed in particular by reports of gold ornaments exhibited in great abundance by Amerindian peoples, particularly in Mesoamerica, Peru, Ecuador and Colombia. The Aztecs regarded gold as the product of the gods and literally called it “divine droppings” (teocuitlatl in Nahuatl), and after the death of Moctezuma II, most of the gold was shipped to Spain. [93] However, for Indigenous peoples in North America, gold was considered useless and they saw much more value in other minerals directly related to its usefulness, such as obsidian, flint and shale. [94] El Dorado is applied to a legendary story in which precious stones were found in fabulous abundance with gold coins. The concept of Eldorado underwent several transformations, and eventually the narratives of the previous myth were also combined with those of a legendary lost city. El Dorado was the term used by the Spanish Empire to describe a mythical tribal chief (zipa) of the Muisca natives in Colombia who covered himself in gold dust as an initiation rite and submerged in Lake Guatavita.

The legends surrounding El Dorado have changed over time from a man to a city, a kingdom and finally an empire. Banknotes (which mature into gold coins) and gold certificates (convertible into gold coins at the issuing bank) supplemented the circulating stock of gold standard money in most industrialized countries of the 19th century. In preparation for World War I, warring nations switched to the fractional gold standard and inflated their currencies to finance the war effort. After the war, the victorious countries, especially Great Britain, gradually restored the convertibility of gold, but international flows of gold via bills of exchange remained under embargo; International deliveries were made exclusively for bilateral trade or to pay war reparations. On August 24, 2020, Israeli archaeologists discovered a fund of ancient Islamic gold coins near the central city of Yavne. Analysis of the extremely rare collection of 425 gold coins revealed that they date back to the late 9th century. The gold coins come from the Abbasid caliphate, which is about 1,100 years old. [117] In 2020, China was the world`s largest gold producer, followed by Russia and Australia. [8] In 2020, a total of approximately 201,296 tonnes of gold are on the surface. [9] This corresponds to a cube, each side measuring approximately 21.7 meters (71 feet). The global consumption of newly produced gold is about 50% in jewelry, 40% in investment and 10% in industry.

[10] The high formability, ductility, resistance to corrosion and most other chemical reactions, as well as the conductivity of electricity have led to the continued use of gold in corrosion-resistant electrical connectors in all types of computer-controlled devices (its primary industrial use). Gold is also used in infrared shielding, colored glass production, gold leaf and dental restoration. Some gold salts are still used as anti-inflammatories in medicine. A sample of the fungus Aspergillus niger was found, which grows from a gold mining solution; It has been found to contain cyanometallic complexes such as gold, silver, copper, iron and zinc. The fungus also plays a role in the solubilization of heavy metal sulphides. [210] The isotope gold 198 (half-life 2.7 days) is used in nuclear medicine, some cancer treatments and other diseases. [191] [192] The price of gold is determined by transactions in the gold and derivatives markets, but a process known as gold fixing in London, which begins in September 1919, provides the industry with a daily reference price. The afternoon fix was introduced in 1968 to provide a price when US markets are open. [158] The gold content (finesse) of alloys is measured in carats (k). Pure gold (commercially called fine gold) is called 24 carats, abbreviated 24 carats.

English gold coins intended for circulation from 1526 to the 1930s were generally a standard 22-carat alloy called crown gold,[152] for hardness (American gold coins intended for circulation after 1837 contain an alloy of 0.900 fine gold or 21.6 kt). [153] Where gold is often found in underground quartz veins and less frequently in other minerals such as pyrite, granite and mica shale. Veins can range from half an inch to several feet wide. 80% of the gold produced today is extracted from these sources (the rest is “alluvial” gold – see below). Knowing where to exploit means “hunting” the gold-bearing veins on the surface underground. It is estimated that about 100,000 tons of gold have been mined in the last 500 years, but even this amount would only fill a cube of 17 m side. The world`s largest gold producer is South Africa, where gold mines are sunk more than 3,000 meters deep into the earth. Gold welding is used to join the components of gold jewelry by brazing at high temperatures or brazing.

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