Platinum

Platinum is the most valued precious metal; its value exceeds even that of Gold . It has a beautiful silver-white colour, and, unlike Silver, does not tarnish. It is unaffected by common household chemicals and will not get damaged or discoloured by chlorine, bleach, or detergents. It is tougher than all precious jewellery metals, though due to its flexible tenacity it still must be alloyed with other metals to prevent it from bending. Natural Platinum usually contains small amounts of the rare element iridium. In jewellery, iridium is alloyed with the Platinum to increase its toughness. Platinum jewellery is usually 90 to 95 percent pure. About Platinum Platinum History (The "unmeltable" steel) Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequently, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the alluvial sands of various rivers, it was first used by pre-Columbian South American natives to produce artefacts. It was referenced in European writings as early as 16th century, but it was not until Antonio de Ulloa published a report on a new metal of Colombian origin in 1748 that it began to be investigated by scientists. Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewellery. Being a heavy metal, it leads to health issues upon exposure to its salts; but due to its corrosion resistance, metallic platinum has not been linked to adverse health effects. Compounds containing platinum, such as cisplatin, oxaliplatin and carboplatin, are applied in chemotherapy against certain types of cancer. Atomic number (number of protons in the nucleus): 78 Atomic symbol (on the periodic table of elements): Pt Atomic weight (average mass of the atom): 195.1 Density: 12.4 ounces per cubic inch (21.45 grams per cubic cm) Phase at room temperature: solid Melting point: 3,215.1 degrees Fahrenheit (1,768.4 degrees Celsius) Boiling point: 6,917 F (3,825 C) Number of natural isotopes (atoms of the same element with a different number of neutrons): 6. There are also 37 artificial isotopes created in a lab. Most common isotopes: Pt-195 (33.83 percent of natural abundance), Pt-194 (32.97 percent of natural abundance), Pt-196 (25.24 percent of natural abundance), Pt-198 (7.16 percent of natural abundance), Pt-192 (0.78 percent of natural abundance), Pt-190 (0.01 percent of natural abundance) In ancient instances, human beings in Egypt and the Americas used platinum for jewelry and decorative portions, often instances mixed with gold. The first recorded reference to platinum become in 1557 while Julius Scaliger, an Italian health practitioner, described a metal discovered in Central America that would not melt and called it "platina," which means "little silver." In 1741, British scientist Charles Wood published a examine introducing platinum as a brand new steel and described some of its attributes and feasible business packages, in line with Peter van der Krogt a Dutch historian. Then, in 1748, Spanish scientist and naval officer Antonio de Ulloa posted a description of a steel that was unworkable and unmeltable. (He at first wrote it in 1735, however his papers have been confiscated by using the British navy.) Back inside the 18th century, platinum changed into the 8th known steel and changed into referred to as "white gold," according to van der Krogt. (Previously recognized metals protected iron, copper, silver, tin, gold, mercury and lead.) In the early 1800s, buddies and colleagues William Hyde Wollaston and Smithson Tennant, each British chemists, produced and offered purified platinum that they remoted using a way developed by Wollaston, consistent with van der Krogt This method includes dissolving platinum ore in a combination of nitric and hydrochloric acids (called aqua regia). After the platinum changed into separated from the rest of the solution, palladium, rhodium, osmium, iridium, and later ruthenium had been all located within the waste. Today, platinum is still extracted using a method much like that developed by means of Wollaston. Samples containing platinum are dissolved in aqua regia, are separated from the relaxation of the solution and byproducts, and are melted at very high temperatures to produce the metal. Platinum is an incredibly rare metal, occurring at a attention of best 0.Half ppm in Earth's crust. It is on occasion flawed for silver (Ag). Platinum is regularly determined chemically uncombined as local platinum and as alloy with the other platinum-group metals and iron broadly speaking. Most frequently the native platinum is discovered in secondary deposits in alluvial deposits. The alluvial deposits utilized by pre-Columbian humans inside the Choc? Department, Colombia are nonetheless a supply for platinum-group metals. Another big alluvial deposit is inside the Ural Mountains, Russia, and it's miles nonetheless mined. In nickel and copper deposits, platinum-group metals occur as sulfides (e.G. (Pt,Pd)S), tellurides (e.G. PtBiTe), antimonides (PdSb), and arsenides (e.G. PtAs2), and as stop alloys with nickel or copper. Platinum arsenide, sperrylite (PtAs2), is a main supply of platinum related to nickel ores inside the Sudbury Basin deposit in Ontario, Canada. At Platinum, Alaska, about 17,000 kg (550,000 oz) were mined among 1927 and 1975. The mine ceased operations in 1990. The rare sulfide mineral cooperite, (Pt,Pd,Ni)S, consists of platinum at the side of palladium and nickel. Cooperite happens within the Merensky Reef in the Bushveld complicated, Gauteng, South Africa. In 1865, chromites were identified within the Bushveld location of South Africa, followed by means of the invention of platinum in 1906. The largest known primary reserves are in the Bushveld complex in South Africa. The huge copper?Nickel deposits close to Norilsk in Russia, and the Sudbury Basin, Canada, are the 2 other big deposits. In the Sudbury Basin, the huge portions of nickel ore processed make up for the truth platinum is present as simplest 0.5 ppm inside the ore. Smaller reserves may be found in the United States, for instance inside the Absaroka Range in Montana. In 2010, South Africa turned into the top manufacturer of platinum, with an nearly seventy seven% share, observed by using Russia at thirteen%; world production in 2010 became 192,000 kg (423,000 lb). Platinum deposits are present within the country of Tamil Nadu, India. Platinum exists in better abundances at the Moon and in meteorites. Correspondingly, platinum is located in slightly higher abundances at web sites of bolide effect on Earth which are associated with resulting submit-impact volcanism, and can be mined economically; the Sudbury Basin is one such example. Chemical Formula Pt Colour Metallic, White Hardness 4 - 4.5 Crystal System Isometric SG 14 - 19 Transparency Opaque Double Refraction None Luster Metallic Cleavage None Mineral Class Platinum
Sumber http://barokongnetwork.blogspot.com