Platinum

Main article: Isotopes of platinum
iso	NA	half-life	DM	DE (MeV)	DP
¹⁹⁰Pt	0.014%	6.5×10¹¹ y	α	3.18	¹⁸⁶Os
¹⁹¹Pt	syn	2.96 d	ε	?	¹⁹¹Ir
¹⁹²Pt	0.782%	Pt is stable with 114 neutrons
¹⁹³Pt	syn	50 y	ε	?	¹⁹³Ir
^193mPt	syn	4.33 d	IT	0.1355e	¹⁹³Pt
¹⁹⁴Pt	32.967%	Pt is stable with 116 neutrons
¹⁹⁵Pt	33.832%	Pt is stable with 117 neutrons
^195mPt	syn	4.02 d	IT	0.1297e	¹⁹⁵Pt
¹⁹⁶Pt	25.242%	Pt is stable with 118 neutrons
¹⁹⁷Pt	syn	19.8913 h	β^-	0.719	¹⁹⁷Au
^197mPt	syn	1.59 h	IT	0.3465	¹⁹⁷Pt
¹⁹⁸Pt	7.163%	Pt is stable with 120 neutrons

References

This page is about the chemical element. For other uses, see Platinum (disambiguation).

Platinum (IPA: /ˈplætɪnəm/) is a chemical element in the periodic table that has the atomic symbol Pt and an atomic number of 78. A heavy, malleable, ductile, precious, grey-white transition metal, platinum is resistant to corrosion and occurs in some nickel and copper ores along with some native deposits. Platinum is used in jewellery, laboratory equipment, electrical contacts, dentistry, and automobile emissions control devices. Platinum bullion has the ISO currency code of XPT.

Notable characteristics

When pure, the metal appears greyish-white and firm. The metal is corrosion-resistant. The catalytic properties of the six platinum family metals are outstanding. For this catalytic property, platinum is used in catalytic converters, incorporated in automobile exhaust systems, as well as tips of spark plugs.

Platinum's wear- and tarnish-resistance characteristics are well suited for making fine jewellery. Platinum is more precious than gold. The price of platinum changes along with its availability, but its price is normally slightly less than twice that of gold. In the 18th century, platinum's rarity made King Louis XV of France declare it the only metal fit for a king.^[1]

Platinum possesses high resistance to chemical attack, excellent high-temperature characteristics, and stable electrical properties. All these properties have been exploited for industrial applications. Platinum does not oxidize in air at any temperature, but can be corroded by cyanides, halogens, sulfur, and caustic alkalis. This metal is insoluble in hydrochloric and nitric acid, but does dissolve in the mixture known as aqua regia (forming chloroplatinic acid). Common oxidation states of platinum include +2, and +4. The +1 and +3 oxidation states are less common, and are often stabilized by metal bonding in bimetallic (or polymetallic) species.The gold is removed from this solution as a precipitate by treatment with iron(II) chloride (FeCl₂). The platinum is precipitated out as impure (NH₄)₂PtCl₆ on treatment with NH₄Cl, leaving H₂PdCl₄ in solution.

Applications

As a catalyst in the catalytic converter, an optional (though often mandatory by law) component of the gasoline-fueled automobile exhaust system (see "Notable characteristics" in this article).
As a catalyst in fuel cells. Reducing the amount of platinum required (and thus cost) is a major focus of fuel cell research.
Certain platinum-containing compounds are capable of crosslinking DNA and kill cells by similar pathways to alkylating chemotherapeutic agents. Cisplatin, carboplatin and oxaliplatin are licensed examples of this class of drugs.
Platinum resistance thermometers.
Electrodes for use in electrolysis.
In the Clark polarographic electrode for measuring oxygen tension.
A wide range of jewelery
As a catalyst in the curing of silicone elastomers.
As a catalyst in glow plugs in some model engines.
Crucibles for high temperature melting of glass (for example) up to 1500°C better if alloyed with rhodium (10–40% of Rh).
In photography, it is sometimes used for archival printmaking. Platinum prints display a greater range of tones than other Black and White printing methods. Additionally platinum's chemical stability makes for extremely long-lasting prints. The disadvantage of this method, in addition to the high cost, is that platinum is less light sensitive and prints must be contact printed at the same size as the negative. Therefore, enlargements can only be made by making an enlarged negative.

History

Naturally-occurring platinum and platinum-rich alloys have been known for a long time. Though the metal was used by pre-Columbian Native Americans, 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 word platinum comes from the Spanish word platina, meaning "little silver."

Platinum was discussed by astronomer Antonio de Ulloa and Don Jorge Juan y Santacilia (1713–1773), both appointed by King Philip V to join a geographical expedition in Peru that lasted from 1735 to 1745. Amongst other things, Ulloa observed the platina del pinto, the unworkable metal found with gold in New Granada (Colombia). British privateers intercepted Ulloa's ship on the return voyage. Though he was well-treated in England, and even made a member of the Royal Society he was prevented from publishing a reference to the unknown metal until 1748. Before that could happen Charles Wood independently isolated the element in 1741. Major finds were discovered in Russia in 1819, which produced around 90% of the global Platinum production at the turn of the 20th century.^[2]

Due to its rarity, greater difficulty to work with and the need to alloy it with (at the time) an even more expensive metal iridium, platinum was only used in a limited way in jewelry at the end of the 19th century. This changed at beginning of the 20th century when most diamond ring mountings and most exclusive jewelry were almost completely made of platinum.^[2]

Occurrence

Platinum ore

Platinum output in 2005

Platinum is an extremely rare metal, occurring as only 5 ppb in the Earth's crust. In 2005, South Africa was the top producer of platinum with almost 80% world share followed by Russia, and Canada, reports the British Geological Survey.^[3]

Platinum is often found chemically uncombined as native platinum and alloyed with iridium as platiniridium. The platinum arsenide, sperrylite (PtAs₂), is a major source of platinum associated with nickel ores in the Sudbury Basin deposit in Ontario, Canada. The rare sulfide mineral cooperite, (Pt,Pd,Ni)S, contains platinum along with palladium and nickel. Cooperite occurs in the Merensky Reef within the Bushveld complex, Gauteng, South Africa.

Platinum, often accompanied by small amounts of other platinum family metals, occurs in alluvial placer deposits in the Witwatersrand of South Africa, Colombia, Ontario, the Ural Mountains, and in certain eastern American states.

Platinum is produced commercially as a by-product of nickel ore processing in the Sudbury deposit. The huge quantities of nickel ore processed makes up for the fact that platinum is present as only 0.5 ppm in the ore.

Platinum exists in relatively higher abundances on the Moon and in asteroids - much terrestrial platinum is mined where asteroids have hit.

Precautions

According to the Centers for Disease Control and Prevention, short-term exposure to platinum salts "may cause irritation of the eyes, nose, and throat" and long-term exposure "may cause both respiratory and skin allergies." The current OSHA standard is 0.002 milligram per cubic meter of air averaged over an 8-hour work shift.^[4]

Certain platinum complexes are used in chemotherapy and show good anti-tumor activity for some tumours. Cisplatin is particularly effective against testicular cancer; cure rate was improved from 10% to 85%.^[5] However, the side effects are severe. Cisplatin causes cumulative, irreversible kidney damage and deafness.^[6]

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), the possibility that platinum free radicals could enter the body and cause adverse effects has merited study. The FDA and other countries have reviewed the issue and found no evidence to suggest toxicity in vivo.^[7]

Rarity and color

An assortment of native platinum nuggets

Platinum's rarity as a metal has caused advertisers to associate it with exclusivity and wealth. "Platinum" credit cards have greater privileges than do "gold" ones. "Platinum awards" are the second highest possible, ranking above gold, silver and bronze, but below "Diamond". For example, a musical album that has sold more than 1,000,000 copies, will be credited as "platinum,” whereas an album that sold more than 10,000,000 copies will be certifed as “diamond.” And some products, such as blenders and vehicles, with a silvery-white color are identified as "platinum". Platinum is considered a precious metal, although its use is not as common as the use of gold or silver. The frame of the Crown of Queen Elizabeth the Queen Mother, manufactured for her Coronation as Consort of King George VI, is made of platinum. It was the first British crown to be made of that metal.

Production

In order to obtain pure platinum, the ore is crushed, made into a slurry, and then mixed with a detergent containing 'collector' molecules. Air is then blown through the mixture, enabling the grains of metal minerals to be separated from the rest of the mixture. This process is called "flotation" or "mineral beneficialness". The next step is smelting.

In 2006, world supply of platinum was of about 217,700 kg or 7 million troy ounces.^[8]^[9] Average Platinum price in 2006 was of US$1200 per troy ounce (~$40/g), representing a significant increase from the 2005 average of US$900 per troy oz.^[3]^[10]

References

1. ^ Platinum. Minerals Zone. Retrieved on 2007-04-05.
2. ^ Smith, Marcell (1913). Diamonds, Pearls and Precious Stones (for the trade). Boston, Grifftih-Stillings Press. , pages 39-40
3. ^ PLATINUM-GROUP METALS (PDF). U.S. Geological Survey, Mineral Commodity Summaries (January 2007). Retrieved on 2007-08-19.
4. ^ Occupational Health Guideline for Soluble Platinum Salts (as Platinum) (PDF). Centers for Disease Control and Prevention. Retrieved on 2007-08-19.
5. ^ Einhorn LH. (1990). "Treatment of testicular cancer: a new and improved model". J. Clin. Oncol. 8 (11): 1777–81.
6. ^ Von Hoff DD, et al (1979). "Toxic effects of cis-dichlorodiammineplatinum(II) in man". Cancer Treat. Rep. 63 (9–10): 1527–31.
7. ^ FDA Backgrounder on Platinum in Silicone Breast Implants. U.S. Food and Drug Administration. Retrieved on 2007-08-19.
8. ^ Johnson Matthey 2006 supply and demand charts
9. ^ "Green curbs hit platinum supply", BBC News, May 20 2002. Retrieved on 2007-08-19.2002">
10. ^ Historical Platinum Charts and Data — London Fix

Los Alamos National Laboratory — Platinum
Nuclides and Isotopes Fourteenth Edition: Chart of the Nuclides, General Electric Company, 1989.
Jefferson Lab — The Element Platinum

External links

• • [ e] Common jewellery materials
Precious metals:	Gold Silver (Sterling silver) Platinum Palladium
Gemstones:	Diamonds Rubies Emeralds Sapphires Amethyst Opals Topaz Aquamarine Tanzanite Alexandrite
Others:	Amber Pearls

4, 6
(mildly basic oxide)
Electronegativity 2.20 (scale Pauling)
Ionization energies 1st: 880 kJ/mol
2nd: 1600 kJ/mol
Atomic radius 135 pm
Atomic radius (calc.
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GOLD refers to one of the following:

GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade).
GOLD (parser) is an open source BNF parser.

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Palladium (IPA: /pəˈleɪdiəm/) is a chemical element with symbol Pd and atomic number 46. It is a rare silver white transition metal of the platinum group, resembling platinum chemically.
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Darmstadtium (IPA: /ˌdɑ(ɹ)mˈʃtatiəm/), formerly called ununnilium (IPA: /ˌjuːnuːˈnɪliəm/, symbol Uun
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<onlyinclude> This is a list of chemical elements, sorted by name and color coded according to type of element.

Given is each element's element symbol, atomic number, atomic mass or most stable isotope, and group and period numbers on the periodic table.
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<onlyinclude> This is a list of chemical elements by symbol, including the current signification used to identify the chemical elements as recognized by the International Union of Pure and Applied Chemistry, as well as proposed and historical signs.
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A table of chemical elements ordered by atomic number and color coded according to type of element. Given is each element's name, element symbol, group and period, Chemical series, and atomic mass (or most stable isotope).
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A group, also known as a family, is a vertical column in the periodic table of the chemical elements. There are 18 groups in the standard periodic table.

The modern explanation of the pattern of the periodic table is that the elements in a group have similar
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In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings:

It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury.

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Periods:]] 1 2 3 4 5 6 7 8
Series Alkalis Alkaline earths Lanthanides Actinides Transition metals Poor metals Metalloids Nonmetals Halogens Noble gases
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A block of the periodic table of elements is a set of adjacent groups. The respective highest-energy electrons in each element in a block belong to the same atomic orbital type.
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A Group 10 element is one in the series of elements in group 10 (IUPAC style) in the periodic table, which consists of the transition metals nickel (Ni), palladium (Pd), platinum (Pt), and darmstadtium (Ds)
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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.

These are: Chemical elements in the sixth period
Group 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
#
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D-Block is an American rap group founded in the 1990s by Sheek Louch, Jadakiss and Styles P as The Lox or The L.O.X.. ^[1] In 2001 the group renamed themselves from "The Lox" to "D-Block".
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Color or colour^[1] (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, yellow, blue, black, etc.
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atomic mass (m_a) is the mass of an atom at rest, most often expressed in unified atomic mass units.^[1] The atomic mass may be considered to be the total mass of protons, neutrons and electrons in a single atom (when the atom is motionless).
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To help compare different orders of magnitude, the following list describes various mass levels between 10⁻³⁶ kg and 10⁵³ kg.

Factor (kg) Value Item
10⁻³⁶ 1.
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This is a list of chemical elements, sorted by relative atomic mass, or more precisely the standard atomic weights, (most stable isotope for artificial elements) and color coded according to type of element.
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electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (e.g., a crystal). Like other elementary particles, the electron is subject to the laws of quantum mechanics, and exhibits both particle-like and wave-like nature.
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Xenon (IPA: /ˈzɛnɒn, ˈziːnɒn/) is a chemical element that has the symbol Xe and atomic number 54.
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Electron

Theoretical estimates of the electron density for the first few hydrogen atom electron orbitals shown as cross-sections with color-coded probability density
Composition: Elementary particle
Family: Fermion
Group: Lepton
Generation: First
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An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. Electron shells are made up of one or more electron subshells, or sublevels
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In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i.e. density, crystal structure, index of refraction, and so forth).
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A solid object is in the states of matter characterized by resistance to deformation and changes of volume. At the microscopic scale, a solid has these properties :

The atoms or molecules that comprise the solid are packed closely together.

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In physics, density is mass m per unit volume V—how heavy something is compared to its size. A small, heavy object, such as a rock or a lump of lead, is denser than a lighter object of the same size or a larger object of the same weight, such as pieces of
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Room temperature (also referred to as ambient temperature) is a common term to denote a certain temperature within enclosed space at which human beings are accustomed.
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The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. Although the phrase would suggest a specific temperature and is commonly and incorrectly used as such in most textbooks and literature, most crystalline compounds
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Platinum

Information about Platinum

Notable characteristics

Applications

History

Occurrence

Precautions

Rarity and color

Production

See also

References

External links