Most platinum isotopes decay by some combination of beta decay and alpha decay. By itself, it has various applications in photography, zinc etchings, indelible ink, plating, mirrors, porcelain coloring, and as a catalyst. Platinum finds use in jewellery, usually as a 90–95% alloy, due to its inertness. The thermal conductivity of high-purity platinum was measured between 300 and 1 000 °K. [52], Platinum, along with the rest of the platinum-group metals, is obtained commercially as a by-product from nickel and copper mining and processing. Basic Physics Division, National Physical Laboratory, Teddington New values are presented and discussed for the thermal conductivities and electrical resistivities of ruthenium, osmium, rhodium, iridium, palladium and platinum over the approximate temperature range 80" to 500°K. [17] The use of platinum(II) acetylacetonate has also been reported. [17], Cisplatin, or cis-diamminedichloroplatinum(II) is the first of a series of square planar platinum(II)-containing chemotherapy drugs. Because platinum is significantly denser than many of its impurities, the lighter impurities can be removed by simply floating them away in a liquid. [39] Platinum also exhibits negative oxidation states at surfaces reduced electrochemically. [25] In 1924, the geologist Hans Merensky discovered a large supply of platinum in the Bushveld Igneous Complex in South Africa. Where a base is desired, the halides have been used in conjunction with sodium acetate. Platinum is often found chemically uncombined as native platinum and as alloy with the other platinum-group metals and iron mostly. Resists corrosion and acid attacks except aqua regia. Cooperite occurs in the Merensky Reef within the Bushveld complex, Gauteng, South Africa. The most common oxidation states of platinum are +2 and +4. 198Pt can undergo alpha decay, but its decay has never been observed (the half-life is known to be longer than 3.2×1014 years); therefore, it is considered stable. [7], As of 2020, the value of platinum is around $32.00 per gram ($1,000 per troy ounce). Its physical characteristics and chemical stability make it useful for industrial applications. Most often the native platinum is found in secondary deposits in alluvial deposits. Pure platinum is a lustrous, ductile, and malleable, silver-white metal. [18], Platinum has six naturally occurring isotopes: 190Pt, 192Pt, 194Pt, 195Pt, 196Pt, and 198Pt. [83], As platinum is a catalyst in the manufacture of the silicone rubber and gel components of several types of medical implants (breast implants, joint replacement prosthetics, artificial lumbar discs, vascular access ports, etc. Chabeneau realized the infusibility of platinum would lend value to objects made of it, and so started a business with Joaquín Cabezas producing platinum ingots and utensils. [17], In 2007, Gerhard Ertl won the Nobel Prize in Chemistry for determining the detailed molecular mechanisms of the catalytic oxidation of carbon monoxide over platinum (catalytic converter). [52], Carl von Sickingen researched platinum extensively in 1772. 190Pt and 198Pt are predicted to have energetically favorable double beta decay paths. Archeologists usually associate the tradition of platinum-working in South America with the La Tolita Culture (circa 600 BC - AD 200), but precise dates and location is difficult, as most platinum artifacts from the area were bought secondhand through the antiquities trade rather than obtained by direct archeological excavation. At times, the platinum seemed malleable, but when it was alloyed with iridium, it would be much more brittle. [63], The most common use of platinum is as a catalyst in chemical reactions, often as platinum black. The NIST manufactured the wires from platinum bar stock with a chemical purity of 99.999% by weight). Several other investigators have since examined the thermal conductivity of platinum and some of their results were reported at the Thermal Conductivity Conference at the National Physical Laboratory last July. [48] To work the metal, they would combine gold and platinum powders by sintering. The previous bar was made of platinum in 1799. At Platinum, Alaska, about 17,000 kg (550,000 ozt) was mined between 1927 and 1975. [82] The National Institute for Occupational Safety and Health has set a recommended exposure limit (REL) for platinum as 1 mg/m3 over an 8-hour workday. Platinum-cobalt, an alloy of roughly three parts platinum and one part cobalt, is used to make relatively strong permanent magnets. Also to make standard weights and measures. Being a heavy metal, it leads to health problems upon exposure to its salts; but due to its corrosion resistance, metallic platinum has not been linked to adverse health effects. [6] Compounds containing platinum, such as cisplatin, oxaliplatin and carboplatin, are applied in chemotherapy against certain types of cancer. [66], From 1889 to 1960, the meter was defined as the length of a platinum-iridium (90:10) alloy bar, known as the international prototype of the meter. Electrical conductivity in metals is a result of the movement of electrically charged particles. The heat transfer characteristics of a solid material are measured by a property called the thermal conductivity , k (or λ), measured in W/m.K . At first sight the conclusions of Powell and Tye are not fully supported by this further work. The calculation for CO 2 filled polyurethane of density 2.00 lb/ft 3 gives 0.035 W/mK . Platinum is one of the least reactive metals. The most abundant of these is 195Pt, comprising 33.83% of all platinum. Heat conduction discussion: Debye Temperature and Thermal Conductivity… Platinum is also used in the petroleum industry as a catalyst in a number of separate processes, but especially in catalytic reforming of straight-run naphthas into higher-octane gasoline that becomes rich in aromatic compounds. [31], Hexachloroplatinic acid mentioned above is probably the most important platinum compound, as it serves as the precursor for many other platinum compounds. 188Pt, 191Pt, and 193Pt decay primarily by electron capture. [28] In 2010, South Africa was the top producer of platinum, with an almost 77% share, followed by Russia at 13%; world production in 2010 was 192,000 kg (423,000 lb). [79] "Platinum awards" are the second highest possible, ranking above "gold", "silver" and "bronze", but below diamond. On the whole this new evidence does not seem to be of sufficient weight to overthrow the conclusion of Powell and Tye that the thermal conductivity is sensibly constant from room temperature to around 900°C. ), the possibility that platinum could enter the body and cause adverse effects has merited study. The thermal conductivity of pure platinum was recently found by Powell and Tye (1) at the National Physical Laboratory, working for the first time on substantial solid specimens, to remain surprisingly constant within 0.5 per cent of 0.73W cm-1°C_1 over the range o to 950°C. Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry. [51], In 1735, Antonio de Ulloa and Jorge Juan y Santacilia saw Native Americans mining platinum while the Spaniards were travelling through Colombia and Peru for eight years. The least stable of these are 165Pt and 166Pt, with half-lives of 260 µs, whereas the most stable is 193Pt with a half-life of 50 years. [35] PtO2 and the less common PtO both decompose upon heating. [12] It reacts vigorously with fluorine at 500 °C (932 °F) to form platinum tetrafluoride. [clarification needed] Other chemists across Europe soon began studying platinum, including Andreas Sigismund Marggraf,[55] Torbern Bergman, Jöns Jakob Berzelius, William Lewis, and Pierre Macquer. [24], In 1865, chromites were identified in the Bushveld region of South Africa, followed by the discovery of platinum in 1906. This started what is known as the "platinum age" in Spain. It is also attacked by chlorine, b… [15] Its resistance to wear and tarnish is well suited to use in fine jewellery. [21][22] It is sometimes mistaken for silver. For example, in the United States, a musical album that has sold more than 1 million copies will be credited as "platinum", whereas an album that has sold more than 10 million copies will be certified as "diamond". [62], Of the 218 tonnes of platinum sold in 2014, 98 tonnes were used for vehicle emissions control devices (45%), 74.7 tonnes for jewelry (34%), 20.0 tonnes for chemical production and petroleum refining (9.2%), and 5.85 tonnes for electrical applications such as hard disk drives (2.7%). [52], Because the other platinum-family members were not discovered yet (platinum was the first in the list), Scheffer and Sickingen made the false assumption that due to its hardness—which is slightly more than for pure iron—platinum would be a relatively non-pliable material, even brittle at times, when in fact its ductility and malleability are close to that of gold. Gold prices are more stable in slow economic times, as gold is considered a safe haven. Chabaneau succeeded in removing various impurities from the ore, including gold, mercury, lead, copper, and iron. [54] Brownrigg also made note of platinum's extremely high melting point and refractoriness toward borax. [40] The negative oxidation states exhibited by platinum are unusual for metallic elements, and they are attributed to the relativistic stabilization of the 6s orbitals.

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