The platinum group or platinum metals is the collective name sometimes used for six chemical elements within the periodic table. These elements are all transition metals, lying in the d-block (groups 8, 9, and 10, periods 5 and 6 - in Mendeleev's original table, this area was called "Group VIII"). Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds, and metals are sometimes described as a lattice of positive ions (cations) in a cloud of electrons. ... A chemical element, often called simply element, is a chemical substance that cannot be divided or changed into other chemical substances by any ordinary chemical technique. ... The periodic table of the chemical elements is a tabular method of displaying the chemical elements, first devised in 1869 by the Russian chemist Dmitri Mendeleev. ... This article is in need of attention. ... D Block is a rap group based in Yonkers, New York. ... A Group 8 element is an element in periodic table group 8 (IUPAC style) in the periodic table, which consists of: Iron (26) Ruthenium (44) Osmium (76) Hassium (108) All of these elements are classed in Group 8 because their valence shell holds four electrons. ... The Group 9 elements are: Cobalt (27) Rhodium (45) Iridium (77) Meitnerium (109) Color coding for these atomic numbers: At room temperature, all are solid; red indicates item is synthetic and does not occur naturally. ... The Group 10 elements are: Nickel (28) Palladium (46) Platinum (78) Darmstadtium (110) Color coding for these atomic numbers: At room temperature, all are solid; red indicates item is synthetic and does not occur naturally. ... A period 5 element is one of the chemical elements in the fifth row (or period) of the periodic table of the elements. ... A period 6 element is one of the chemical elements in the sixth row (or period) of the periodic table of the elements, including the Lanthanides. ... Mendeleyevs portrait by Ilya Repin. ...

The six platinum metals are: ruthenium, rhodium, palladium, osmium, iridium, and platinum. They have similar physical and chemical properties, and tend to occur together in the same mineral deposits. General Name, Symbol, Number ruthenium, Ru, 44 Chemical series transition metals Group, Period, Block 8, 5, d Appearance silvery white metallic Atomic mass 101. ... Rh redirects here. ... General Name, Symbol, Number palladium, Pd, 46 Chemical series transition metals Group, Period, Block 10, 5, d Appearance silvery white metallic Atomic mass 106. ... General Name, Symbol, Number osmium, Os, 76 Chemical series transition metals Group, Period, Block 8, 6, d Appearance silvery, blue cast Atomic mass 190. ... General Name, Symbol, Number iridium, Ir, 77 Chemical series transition metals Group, Period, Block 9, 6, d Appearance silvery white Atomic mass 192. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Atomic mass 195. ...

History

Naturally occurring platinum and platinum-rich alloys have been known for a long time. Though the metal was used by pre-Columbian peoples, the first European reference to platinum appears in 1557 in the writings of the Italian humanist Julius Caesar Scaliger (1484-1558) as a description of a mysterious metal found in Central American mines between Darién (Panama) and Mexico ("up until now impossible to melt by any of the Spanish arts"). The term Pre-Columbian is used to refer to the cultures of the New World in the era before significant European influence. ... Events Spain is effectively bankrupt. ... Julius Caesar Scaliger (1484-1558), humanist scholar. ... Events January 25 - Peter Arbues, chief of the Spanish Inquisition, is assassinated when he is praying in the cathedral at Saragossa, Spain July 6 - Portuguese sea captain Diogo Cão finds the mouth of Congo River December 5 - Pope Innocent VIII gives the inquisition a mission to hunt heretics and... Events January 7 - French troops led by Francis, Duke of Guise take Calais, the last continental possession of England July 13 - Battle of Gravelines: In France, Spanish forces led by Count Lamoral of Egmont defeat the French forces of Marshal Paul des Thermes at Gravelines. ...

The Spaniards named the metal platina, or "little silver", when they first encountered it in Colombia. They regarded platinum as an unwanted impurity in the silver they were mining.

Properties

The catalytic properties of the six platinum group metals are outstanding. Platinum's wear and tarnish resistance characteristics are well suited for making fine jewelry. Other distinctive properties include resistance to chemical attack, excellent high-temperature characteristics, and stable electrical properties. All these properties have been exploited for industrial applications. In chemistry and biology, catalysis (in Greek meaning to annul) is the acceleration of the rate of a chemical reaction by means of a substance, called a catalyst, that is itself unchanged chemically by the overall reaction. ... Jewelry (the American spelling; spelled jewellery in Commonwealth English) consists of ornamental devices worn by persons, typically made with gems and precious metals. ... Electricity is a property of matter that results from the presence of electric charge. ...

Applications

Platinum, platinum alloys, and iridium are used as crucible materials for the growth of single crystals, especially oxides. The chemical industry uses a significant amount of either platinum or a platinum-rhodium alloy catalyst in the form of gauze to catalyze the partial oxidation of ammonia to yield nitric oxide, which is the raw material for fertilizers, explosives, and nitric acid.

In recent years, a number of platinum-group metals have become important as catalysts in synthetic organic chemistry. Ruthenium dioxide is used as coatings on dimensionally stable titanium anodes used in the production of chlorine and caustic.

Platinum supported catalysts are used in the refining of crude oil, reforming, and other processes used in the production of high-octane gasoline and aromatic compounds for the petrochemical industry. Since 1979, the automotive industry has emerged as the principal consumer of platinum-group metals. Palladium, platinum, and rhodium have been used as oxidation catalyst in catalytic converters to treat automobile exhaust emissions. A wide range of platinum-group metal alloy compositions are used in low-voltage and low-energy contacts, thick- and thin-film circuits, thermocouples and furnace components, and electrodes. ... Automakers are companies that produce automobiles. ... A catalytic converter is a device used to reduce the emissions from an internal combustion engine. ...

Sources of platinum group metals

• Platinum is often found in a native state and the ore sperrylite (platinum arsenide, PtAs₂) is a major source of this metal. A naturally occurring platinum/iridium alloy is platiniridium and this metal is also found in the mineral cooperite (platinum sulfide, PtS). Platinum is often accompanied by small amounts of other platinum family metals which are found in alluvial deposits in Colombia, Ontario, the Ural Mountains, and in certain western American states. Platinum is also produced commercially as a by-product of nickel ore processing. The huge quantities of nickel ore processed makes up for the fact that platinum makes up only two parts per million of the ore. South Africa with vast deposits in the Bushveld complex is the world's largest producer of platinum followed by Russia.

• Osmium is found in iridiosmium a naturally occurring alloy of iridium and osmium and in platinum-bearing river sands in the Ural Mountains, North, and South America. It also occurs in nickel-bearing ores found in the Sudbury, Ontario region with other platinum group metals. Even though the quantity of platinum metals found in these ores is small, the large volume of nickel ores processed makes commercial recovery possible.

• Iridium is found uncombined in nature with platinum and other platinum group metals in alluvial deposits. Naturally occurring iridium alloys include osmiridium and iridiosmium, both of which are mixtures of iridium and osmium. It is recovered commercially as a by-product from nickel mining and processing.

• Ruthenium is generally found in ores with the other platinum group metals in the Ural Mountains and in North and South America. Small but commercially important quantities are also found in pentlandite extracted from Sudbury, Ontario and in pyroxenite deposits in South Africa. Ruthenium is commercially isolated through a complex chemical process in which hydrogen is used to reduce ammonium ruthenium chloride yielding a powder. The powder is then consolidated by powder metallurgy techniques or by argon-arc welding.

• The industrial extraction of rhodium is complex as the metal occurs in ores mixed with other metals such as palladium, silver, platinum, and gold. It is found in platinum ores and obtained free as a white inert metal which it is very difficult to fuse. Principal sources of this element are located in river sands of the Ural Mountains, in North and South America and also in the copper-nickel sulfide mining area of the Sudbury Basin region. Although the quantity at Sudbury is very small, the large amount of nickel ore processed makes rhodium recovery cost effective. However, the annual world production of this element is only 7 or 8 tons and there are very few rhodium minerals.

• Palladium is found as a free metal and alloyed with platinum and gold with platinum group metals in placer deposits of the Ural Mountains, Australia, Ethiopia, South and North America. However it is commercially produced from nickel-copper deposits found in South Africa and Ontario (the huge volume of ore processed makes this extraction profitable in spite of its low concention in these ores).

Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a mineral deposit containing a metal or other valuable resource in economically viable concentrations. ... Sperrylite is a platinum arsenide mineral with formula: PtAs2. ... General Name, Symbol, Number arsenic, As, 33 Chemical series metalloids Group, Period, Block 15, 4, p Appearance metallic gray Atomic mass 74. ... This article is about minerals in the geologic sense; for nutrient minerals see dietary mineral; for the band see Mineral (band). ... Cooperite is a grey mineral consisting of platinum sulfide (PtS), general in combinations with sulfides of other elements such as palladium and nickel (PdS and NiS). ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... Alluvium is soil land deposited by a river or other running water. ... Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Official languages English, French (in some areas) Capital Toronto Largest city Toronto Lieutenant-Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Parliamentary representation  - House seat  - Senate seats 106 24 Area  - Total  - % water Ranked 4th 1,076,395... Map of Ural Mountains The Ural Mountains (Russian: Уральские горы = Урал) also known simply as the Urals and as the Riphean Mountains in Greco-Roman antiquity, is a mountain range that runs roughly north and south through western Russia. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... The Bushveld igneous complex contains one of the richest ore deposits on Earth. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Atomic mass 195. ... World map showing North America A satellite composite image of North America North America is a continent in the northern hemisphere bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the south by the Caribbean Sea, and on the west by the... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... Greater Sudbury (2001 census population 155,219) is a city in Northern Ontario. ... Pentlandite is a iron-nickel sulfide, (Fe,Ni)9S8. ... Pyroxenite is a rock consisting essentially of minerals of the pyroxene group, such as augite and diallage, hypersthene, bronzite or enstatite. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... Fumes from hydrochloric acid and ammonia forming a white cloud of ammonium chloride Ammonium is also an old name for the Siwa oasis in western Egypt. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Atomic mass 39. ... Manual Metal Arc welding, also known as stick or MMA welding is one of the most common forms of welding. ... General Name, Symbol, Number silver, Ag, 47 Chemical series transition metals Group, Period, Block 11, 5, d Appearance lustrous white metal Atomic mass 107. ... It has been suggested that Gold bar be merged into this article or section. ... Sudbury Basin is the oval structure, next to the much younger lake-filled Wanapitei crater The Sudbury Basin is the second largest impact crater on earth, and a major geologic structure in Ontario, Canada. ... The word ton or tonne is derived from the Old English tunne, and ultimately from the Old French tonne, and referred originally to a large cask with a capacity of 252 wine gallons, which holds approximately 2100 pounds of water. ... A sluice box used in placer mining Placer mining (pronounced plass-er) is a open-pit or open-cast form of mining by which certain valuable minerals are extracted from the earth without tunneling. ... Map of Ural Mountains The Ural Mountains (Russian: Уральские горы = Урал) also known simply as the Urals and as the Riphean Mountains in Greco-Roman antiquity, is a mountain range that runs roughly north and south through western Russia. ... General Name, Symbol, Number nickel, Ni, 28 Chemical series transition metals Group, Period, Block 10, 4, d Appearance lustrous, metallic Atomic mass 58. ... General Name, Symbol, Number copper, Cu, 29 Chemical series transition metals Group, Period, Block 11, 4, d Appearance metallic brown Atomic mass 63. ... Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Official languages English, French (in some areas) Capital Toronto Largest city Toronto Lieutenant-Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Parliamentary representation  - House seat  - Senate seats 106 24 Area  - Total  - % water Ranked 4th 1,076,395...

References

• USGS Minerals Information Platinum-Group Metals Statistics and Information.