Platinum does notcorrode, even at high temperatures, and is therefore considered anoble metal. Consequently, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in thealluvial sands of various rivers, it was first used bypre-ColumbianSouth American natives to produce artifacts. It was referenced in European writings as early as the 16th century, but it was not untilAntonio de Ulloa published a report on a new metal ofColombian origin in 1748 that it began to be investigated by scientists.
Platinum is a lustrous,ductile, andmalleable, silver-white metal.[16] Platinum is more ductile than gold,silver orcopper, thus being the most ductile of pure metals.[17][18]
Its physical characteristics and chemical stability make it useful for industrial applications.[19] Its resistance to wear and tarnish is well suited to use in finejewelry.[20]
Platinum does notcorrode, and bulk platinum does not oxidize in air at any temperature, but heated metal wires lose weight faster in air or oxygen than it does in a vacuum. The suggestion is that Pt forms a thin surface film ofPtO2 that decomposes when heated above 500 °C.[21]
The most commonoxidation states of platinum are +2 and +4. The +1 and +3 oxidation states are less common, and are often stabilized by metal bonding in bimetallic (or polymetallic) species. Tetracoordinate platinum(II) compounds tend to adopt 16-electronsquare planar geometries. Although elemental platinum is generally unreactive, it is attacked bychlorine,bromine,iodine, andsulfur. It reacts vigorously with fluorine at 500 °C (932 °F) to formplatinum tetrafluoride.[22] Platinum is insoluble inhydrochloric andnitric acid, but dissolves in hotaqua regia (a mixture of nitric and hydrochloric acids), to form aqueouschloroplatinic acid,H2PtCl6:[23][24]
Pt + 4 HNO3 + 6 HCl → H2PtCl6 + 4 NO2 + 4 H2O
As asoft acid, thePt2+ ion has a great affinity for sulfide and sulfur ligands. Numerous DMSO complexes have been reported and care is taken in the choosing of reaction solvents.[25]
Platinum has six naturally occurringisotopes:190 Pt,192 Pt,194 Pt,195 Pt,196 Pt, and198 Pt. The mostabundant of these is195 Pt, comprising 33.83% of all platinum; it is the only stable isotope with a non-zerospin, of1/2, and it is favorable for use in195 Pt NMR. Due to its spin and large abundance,195 Pt satellite peaks are also often observed in1 H and31 P NMR spectroscopy (e.g., for Pt-phosphine and Pt-alkyl complexes). The radioactive190 Pt is the least abundant of these at only 0.012%; it undergoesalpha decay with a half-life of 4.83×1011 years, causing the very low activity of 16.8Bq/kg of natural platinum.[27] The decay of this isotope has some use inisotope geology, though not directly for dating.[28]
The other natural isotopes are theoretically capable ofalpha decay also, but this has never been observed, and therefore they are considered stable.[29] Platinum also has 38 synthetic isotopes ranging in atomic mass from 165 to 208, making the total number of known isotopes 44. The most stable of theseradioisotopes is193 Pt, with a half-life of 50 years. Most platinum isotopes decay by some combination ofbeta decay and (on the proton-rich side) alpha decay.188 Pt,191 Pt, and193 Pt decay only byelectron capture (besides the very small alpha branch of the first).190 Pt and198 Pt are predicted to have energetically favorabledouble beta decay paths.[27]
A native platinum nugget,Kondyor mine,Khabarovsk KraiPlatinum-palladium ore, Stillwater mine, Beartooth Mountains, Montana, USSulfidic serpentinite (platinum-palladium ore) from Stillwater Mine, Beartooth Mountains, Montana, USA
Platinum is an extremely rare metal onEarth,[30] occurring at a concentration of only 0.005ppm inEarth's crust.[31][32] Platinum is often found chemically uncombined as native platinum and asalloy with the other platinum-group metals mostly. Most often native platinum is found in secondary deposits amongalluvial deposits. The alluvial deposits used bypre-Columbian people in theChocó Department,Colombia are still a source for platinum-group metals. Another large alluvial deposit is in theUral Mountains, Russia, and it is still mined.[24]
In 1865,chromites were identified in the Bushveld region of South Africa, followed by the discovery of platinum in 1906.[35] In 1924, the geologistHans Merensky discovered a large supply of platinum in theBushveld Igneous Complex in South Africa. The specific layer he found, named theMerensky Reef, contains around 75% of the world's known platinum.[36][37] The large copper–nickel deposits nearNorilsk inRussia, and theSudbury Basin,Canada, are the two other large deposits. In the Sudbury Basin, the huge quantities of nickel ore processed make up for the fact platinum is present as only 0.5ppm in the ore. Smaller reserves can be found in the United States,[37] for example in theAbsaroka Range inMontana.[38] 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).[39]
Advanced techniques to finding platinum deposits by studying ground water found some evidence of new deposits in the state ofTamil Nadu,India.[40]
Platinum exists in somewhat higher quantity on theMoon and in meteorites. Correspondingly, platinum is found in slightly higher abundances at sites ofbolide impact on Earth that are associated with resulting post-impact volcanism and can be mined economically; theSudbury Basin is one such example.[41]
Hexachloroplatinic acid mentioned above is probably the most important platinum compound, as it serves as the precursor for many other platinum compounds. By itself, it has various applications in photography, zinc etchings,indelible ink, plating, mirrors, porcelain coloring, and as a catalyst.[42]
Treatment of hexachloroplatinic acid with an ammonium salt, such asammonium chloride, givesammonium hexachloroplatinate,[23] which is relatively insoluble in ammonium solutions. Heating this ammonium salt in the presence of hydrogen reduces it to elemental platinum.Potassium hexachloroplatinate is similarly insoluble, and hexachloroplatinic acid has been used in the determination of potassium ions bygravimetry.[43]
Platinum(IV) oxide,PtO2, also known as "Adams' catalyst", is a black powder that is soluble inpotassium hydroxide (KOH) solutions and concentrated acids.[45]PtO2 and the less commonPtO both decompose upon heating.[16] Platinum(II,IV) oxide,Pt3O4, is formed in the following reaction:
Platinum exhibits negative oxidation states at surfaces reduced electrochemically,[47] and several "platinides" have been synthesized in which platinum exhibits oxidation states ranging from −1 to −2. The negative oxidation states exhibited by platinum are unusual for metallic elements, and they are attributed to the relativistic stabilization of the 6s orbitals.[48] Barium platinides include BaPt,Ba 3Pt 2, andBa 2Pt.[49] Caesium platinide,Cs 2Pt, a dark-red transparent crystalline compound[50] has been shown to contain Pt2− anions.[48] The "platinumGrignard" Pt(MgCl)2·nTHF conjecturally contains Pt2− as well.[51]
It is predicted that even the cationPtO2+ 4 in which platinum exists in the +10 oxidation state may be achievable.[52]
Cisplatin, orcis-diamminedichloroplatinum(II) is the first of a series of square planar platinum(II)-containing chemotherapy drugs.[53] Others includecarboplatin andoxaliplatin. These compounds are capable ofcrosslinkingDNA, and kill cells by similar pathways to alkylatingchemotherapeutic agents.[54] (Side effects of cisplatin include nausea and vomiting, hair loss, tinnitus, hearing loss, and nephrotoxicity.)[55][56]
Platinum exposure has shown no adverse effects with animal life as it is one of the least reactive metals.[57]
As platinum is acatalyst in the manufacture of thesilicone rubber and gel components of several types ofmedical implants (breast implants, joint replacement prosthetics, artificial lumbar discs, vascular access ports, etc.), the possibility that platinum could enter the body and cause adverse effects has been studied. TheFood and Drug Administration and other institutions have reviewed the issue and found no evidence to suggest toxicityin vivo.[58][59][60]
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 currentOSHA standard is 2 micrograms per cubic meter of air averaged over an 8-hour work shift.[61]
Archaeologists have discovered traces of platinum in the gold used in ancient Egyptian burials. For example, a small box from burial ofShepenupet II was found to be decorated with gold-platinum hieroglyphics.[62] However, the extent of early Egyptians' knowledge of the metal is unclear. It is quite possible they did not recognize there was platinum in their gold.[63][64]
The first European reference to platinum appears in 1557 in the writings of theItalian humanistJulius Caesar Scaliger as a description of an unknown noble metal found betweenDarién and Mexico, "which no fire nor any Spanish artifice has yet been able to liquefy".[69] From their first encounters with platinum, the Spanish generally saw the metal as a kind of impurity in gold, and it was treated as such. It was often simply thrown away, and there was an official decree forbidding theadulteration of gold with platinum impurities.[68]
In 1735,Antonio de Ulloa andJorge Juan y Santacilia saw Native Americans mining platinum while the Spaniards were travelling through Colombia and Peru for eight years. Ulloa and Juan found mines with the whitish metal nuggets and took them home to Spain. Antonio de Ulloa returned to Spain and established the first mineralogy lab in Spain and was the first to systematically study platinum, which was in 1748. His historical account of the expedition included a description of platinum as being neither separable norcalcinable. Ulloa also anticipated the discovery of platinum mines. After publishing the report in 1748, Ulloa did not continue to investigate the new metal. In 1758, he was sent to superintend mercury mining operations inHuancavelica.[69]
In 1750, after studying the platinum sent to him by Wood, Brownrigg presented a detailed account of the metal to theRoyal Society, stating that he had seen no mention of it in any previous accounts of known minerals.[71] Brownrigg also made note of platinum's extremely high melting point and refractoriness towardborax.[clarification needed] Other chemists across Europe soon began studying platinum, includingAndreas Sigismund Marggraf,[72]Torbern Bergman,Jöns Jakob Berzelius,William Lewis, andPierre Macquer. In 1752,Henrik Scheffer published a detailed scientific description of the metal, which he referred to as "white gold", including an account of how he succeeded in fusing platinum ore with the aid ofarsenic. Scheffer described platinum as being less pliable than gold, but with similar resistance to corrosion.[69]
Karl von Sickingen researched platinum extensively in 1772. He succeeded in makingmalleable platinum byalloying it with gold, dissolving the alloy in hotaqua regia, precipitating the platinum withammonium chloride, igniting the ammonium chloroplatinate, and hammering the resulting finely divided platinum to make it cohere.Franz Karl Achard made the first platinum crucible in 1784. He worked with the platinum by fusing it with arsenic, then latervolatilizing the arsenic.[69]
Because the other platinum-family members were not discovered yet (platinum was the first), Scheffer and Sickingen made the false assumption that due to its hardness—which is slightly more than for pureiron—platinum would be a relatively non-pliable material, even brittle at times, when in fact its ductility exceeds that of gold and its malleability similar to gold's. Their assumptions could not be avoided because the platinum they experimented with was highly contaminated with minute amounts of platinum-family elements such asosmium andiridium, amongst others, which embrittled the platinum alloy. Alloying this impure platinum residue called "plyoxen"[citation needed] with gold as the only solution at the time to obtain a pliable compound. Presently, very pure platinum is readily available, and extremely long wires can easily be drawn from pure platinum due to its crystalline structure, which is similar to that of many soft metals.[73]
In 1786,Charles III of Spain provided a library and laboratory toPierre-François Chabaneau to aid in his research of platinum. Chabaneau succeeded in removing various impurities from the ore, including gold, mercury, lead, copper, and iron. This led him to believe he was working with a single metal, but in truth the ore still contained the yet-undiscovered platinum-group metals. This led to inconsistent results in his experiments. At times, the platinum seemed malleable, but when it was alloyed with iridium, it would be much morebrittle. Sometimes the metal was entirely incombustible, but when alloyed with osmium, it would volatilize. After several months, Chabaneau succeeded in producing 23 kilograms of pure, malleable platinum by hammering and compressing the sponge form while white-hot. 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. This started what is known as the "platinum age" in Spain.[69]
Platinum, along with the rest of theplatinum-group metals, is obtained commercially as a by-product fromnickel andcopper mining and processing. Duringelectrorefining of copper, noble metals such as silver, gold and the platinum-group metals as well asselenium andtellurium settle to the bottom of the cell as "anode mud", which forms the starting point for the extraction of the platinum-group metals.[74]
If pure platinum is found inplacer deposits or other ores, it is isolated from them by various methods of subtracting impurities. Because platinum is significantly denser than many of its impurities, the lighter impurities can be removed by simply floating them away in a liquid. Platinum isparamagnetic, whereas nickel and iron are bothferromagnetic. These two impurities are thus removed by running an electromagnet over the mixture. Because platinum has a higher melting point than most other substances, many impurities can be burned or melted away without melting the platinum. Finally, platinum is resistant to hydrochloric and sulfuric acids, whereas other substances are readily attacked by them. Metal impurities can be removed by stirring the mixture in either of the two acids and recovering the remaining platinum.[75]
One suitable method for purification for the raw platinum, which contains platinum, gold, and the other platinum-group metals, is to process it withaqua regia, in which palladium, gold and platinum are dissolved, whereas osmium, iridium, ruthenium and rhodium stay unreacted. The gold is precipitated by the addition ofiron(II) chloride and after filtering off the gold, the platinum is precipitated asammonium chloroplatinate by the addition ofammonium chloride. Ammonium chloroplatinate can be converted to platinum by heating.[76] Unprecipitated hexachloroplatinate(IV) may be reduced with elementalzinc, and a similar method is suitable for small scale recovery of platinum from laboratory residues.[77] Mining and refining platinum has environmental impacts.[78]
An aerial photograph of a platinum mine in South Africa.Time trend of platinum production[79]
Of the 218 tonnes of platinum sold in 2014, 98 tonnes were used forvehicle emissions control devices (45%), 74.7 tonnes for jewelry (34%), 20.0 tonnes for chemical production andpetroleum refining (9.2%), and 5.85 tonnes for electrical applications such as hard disk drives (2.7%). The remaining 28.9 tonnes went to various other minor applications, such as medicine andbiomedicine, glassmaking equipment, investment, electrodes, anticancer drugs,oxygen sensors,spark plugs andturbine engines.[82]
The most common use of platinum is as acatalyst in chemical reactions, often asplatinum black. It has been employed as a catalyst since the early 19th century, when platinum powder was used to catalyze the ignition of hydrogen. In an automobilecatalytic converter, it completes the combustion of low concentrations of unburned hydrocarbons from the exhaust into carbon dioxide and water vapor. Platinum is also used in the petroleum industry as a catalyst in a number of separate processes, but especially incatalytic reforming of straight-runnaphthas into higher-octane gasoline that becomes rich in aromatic compounds.PtO2, also known asAdams' catalyst, is used as a hydrogenation catalyst, specifically forvegetable oils.[42] Platinum also strongly catalyzes the decomposition ofhydrogen peroxide intowater and oxygen[83] and it is used infuel cells[84] as a catalyst for the reduction ofoxygen.[85]
From 1889 to 1960, themeter was defined as the length of a platinum-iridium (90:10) alloy bar, known as theinternational prototype meter. The previous bar was made of platinum in 1799. Until May 2019, thekilogram was defined as the mass of theinternational prototype of the kilogram, a cylinder of the same platinum-iridium alloy made in 1879.[88]
The Standard PlatinumResistance Thermometer (SPRT) is one of the four types of thermometers used to define theInternational Temperature Scale of 1990 (ITS-90), the international calibration standard for temperature measurements. The resistance wire in the thermometer is made of pure platinum (NIST manufactured the wires from platinum bar stock with a chemical purity of 99.999% by weight).[89][90] In addition to laboratory uses, Platinum Resistance Thermometry (PRT) also has many industrial applications, industrial standards include ASTM E1137 and IEC 60751.
Platinum is aprecious metalcommodity; itsbullion has theISO currency code of XPT. Coins, bars, and ingots are traded or collected. Platinum finds use in jewelry, commonly sold as .999 or .9995 fine. It is used for this purpose for its prestige and inherent bullion value.[92][93]
In watchmaking,Rolex,[94]Vacheron Constantin,[95]Patek Philippe,[96]Breitling,[97] and other master watchmakers use platinum in select watches. Watchmakers appreciate the unique properties of platinum, as it is more durable than gold, but similar to gold as it does not tarnish.[98]
During periods of sustained economic stability and growth, the price of platinum can exceed that of the price of gold.[99] As an investment, platinum is similar to gold in being a relatively low risk investment, or "safe-haven", in times of economic crisis.[100] When the price of gold has exceeded that of platinum, many buyers in major markets, including the famous Dubai "gold souk" have turned to buying platinum instead for investment and for jewelry.[101]
In the 18th century KingLouis XV of France said of platinum that it is "the only metal fit for a king", owing to platinum's scarcity, traits, and intrinsic value.[102]
As of 2024, the American multinational warehouse club chain,Costco, sells platinum bars on its website.[103]
1,000 cubic centimeters of 99.9% pure platinum, worth about US$696,000 as of 29 Jun 2016 ($911,884 adjusted for inflation)[104]
In the laboratory, platinum wire is used for electrodes; platinum pans and supports are used inthermogravimetric analysis because of the stringent requirements of chemical inertness upon heating to high temperatures (~1000 °C). Platinum is used as an alloying agent for various metal products, including fine wires, noncorrosive laboratory containers, medical instruments, dental prostheses, electrical contacts, and thermocouples. Platinum-cobalt, an alloy of roughly three parts platinum and one part cobalt, is used to make relatively strong permanentmagnets.[42] Platinum-based anodes are used in ships, pipelines, and steel piers.[24] Platinum drugs are used to treat a wide variety of cancers, including testicular and ovarian carcinomas, melanoma, small-cell and non-small-cell lung cancer, myelomas and lymphomas.[105]
Platinum's rarity as a metal has caused advertisers to associate it with exclusivity and wealth. "Platinum"debit and credit cards have greater privileges than "gold" cards.[106] "Platinum awards" are frequently the highest, or near highest possible, often ranking above "gold", "silver" and "bronze". In the United States, a musical album that has sold more than 1 million copies will be credited as "platinum".[107] Some products, such as blenders and vehicles, with a silvery-white color are identified as "platinum". The frame of theCrown of Queen Elizabeth The Queen Mother, manufactured for her coronation as Consort ofKing George VI, is made of platinum. It was the first British crown to be made of this particular metal.[108]
^abcArblaster, John W. (2018).Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International.ISBN978-1-62708-155-9.
^Pt(−2) has been observed in Cs2Pt, seeKarpov, Andrey; Nuss, Jürgen; Wedig, Ulrich; Jansen, Martin (13 October 2003). "Cs2Pt: A Platinide(-II) Exhibiting Complete Charge Separation".Angewandte Chemie International Edition.42 (39). Wiley:4818–4821.doi:10.1002/anie.200352314.ISSN1433-7851..
^Pt(0) has been observed inorganoplatinum compounds, e. g. (PPh3)2PtC2H4; seeCheng, P.-T.; Nyburg, S. C. (1972). "The Crystal and Molecular Structure of bis(triphenylphosphine)-(ethylene)platinum, (PPh3)2PtC2H4".Canadian Journal of Chemistry.50 (6):912–916.doi:10.1139/v72-142.
^Pt(I) has been observed in [Pt2(CO)6]2+; seeXu, Qiang; Heaton, Brian T.; Jacob, Chacko; Mogi, Koichi; Ichihashi, Yuichi; Souma, Yoshie; Kanamori, Kan; Eguchi, Taro (2000). "Hexacarbonyldiplatinum(I). Synthesis, spectroscopy, and density functional calculation of the first homoleptic, dinuclear platinum(I) carbonyl cation, [{Pt(CO)3}2]2+, formed in concentrated sulfuric acid".Journal of the American Chemical Society.122 (29):6862–6870.doi:10.1021/ja000716u.
^Pt(III) has been observed; seeO'Halloran, Thomas V.; Lippard, Stephen J. (1985). "The Chemistry of Platinum in the +3 Oxidation State".Israel Journal of Chemistry.25 (2):130–137.doi:10.1002/ijch.198500021.
^Schwartz, M. (2002).Encyclopedia and Handbook of Materials, Parts and Finishes (2nd ed.). CRC Press.ISBN9781420017168.
^Vaccari, J.A.; Clauser, H.R.; Brady, G.S. (2002).Materials handbook: an encyclopedia for managers, technical professionals, purchasing and production managers, technicians, and supervisors (15th ed.). McGraw-Hill.ISBN9780071360760.
^Craig, Bruce D; Anderson, David S; International, A.S.M. (January 1995)."Platinum".Handbook of corrosion data. ASM International. pp. 8–9.ISBN978-0-87170-518-1.Archived from the original on 24 March 2017.
^abcCRC contributors (2007–2008). "Platinum". In Lide, David R. (ed.).CRC Handbook of Chemistry and Physics. Vol. 4. New York: CRC Press. p. 26.ISBN978-0-8493-0488-0.
^"The History of Platinum".Alaska Community Database Online. ExploreNorth.Archived from the original on 22 December 2010. Retrieved12 April 2011.Platinum is located on the Bering Sea coast, below Red Mountain on the south spit of Goodnews Bay.
^Loferski, P. J. (July 2012)."Platinum–Group Metals"(PDF). USGS Mineral Resources Program.Archived(PDF) from the original on 7 July 2012. Retrieved17 July 2012.
^Smith, G. F.; Gring, J. L. (1933). "The Separation and Determination of the Alkali Metals Using Perchloric Acid. V. Perchloric Acid and Chloroplatinic Acid in the Determination of Small Amounts of Potassium in the Presence of Large Amounts of Sodium".Journal of the American Chemical Society.55 (10):3957–3961.Bibcode:1933JAChS..55.3957S.doi:10.1021/ja01337a007.
^Ahrens, Sebastian; Strassner, Thomas (2006). "Detour-free synthesis of platinum-bis-NHC chloride complexes, their structure and catalytic activity in the CH activation of methane".Inorganica Chimica Acta.359 (15):4789–4796.doi:10.1016/j.ica.2006.05.042.
^Ghilane, J.; Lagrost, C.; Guilloux-Viry, M.; Simonet, J.; et al. (2007). "Spectroscopic Evidence of Platinum Negative Oxidation States at Electrochemically Reduced Surfaces".Journal of Physical Chemistry C.111 (15):5701–7.doi:10.1021/jp068879d.
^Karpov, Andrey; Konuma, Mitsuharu; Jansen, Martin (2006). "An experimental proof for negative oxidation states of platinum: ESCA-measurements on barium platinides".Chemical Communications.44 (8):838–840.doi:10.1039/b514631c.PMID16479284.
^Karpov, Andrey; Nuss, Jürgen; Wedig, Ulrich; Jansen, Martin (2003). "Cs2Pt: A Platinide(-II) Exhibiting Complete Charge Separation".Angewandte Chemie International Edition.42 (39):4818–21.Bibcode:2003ACIE...42.4818K.doi:10.1002/anie.200352314.PMID14562358.
^Riddell, Imogen A.; Lippard, Stephen J. (2018). "Cisplatin and Oxaliplatin:Our Current Understanding of Their Actions". In Sigel, Astrid; Sigel, Helmut; Freisinger, Eva; Sigel, Roland K. O. (eds.).Metallo-Drugs:Development and Action of Anticancer Agents. Metal Ions in Life Sciences. Vol. 18. pp. 1–42.doi:10.1515/9783110470734-007.ISBN978-3-11-046984-4.PMID29394020.
^Carinder, James A.; Morrison, Pilar M.; Morrison, David G.; Jack E. Saux III (7 July 2014).Practical Oncology Protocols. Mill City Press, Incorporated. p. 22.ISBN978-1-62652-816-1.Archived from the original on 9 November 2017. Retrieved11 June 2016.
^"Chapter 6.11 Platinum"(PDF),Air Quality Guidelines (2nd ed.), WHO Regional Office for Europe, Copenhagen, Denmark, 2000,archived(PDF) from the original on 18 October 2012
^Kauffman, George B.; Teter, Larry A. & Rhoda, Richard N. (1963). "Recovery of Platinum from Laboratory Residues".Inorganic Syntheses. Inorg. Synth. Vol. 7. pp. 232–6.doi:10.1002/9780470132388.ch61.ISBN978-0-470-13238-8.{{cite book}}:ISBN / Date incompatibility (help)
^Laramie, James; Dicks, Andrew (2003).Fuel Cell System Explained. John Wiley & Sons Ltd.ISBN978-0-470-84857-9.
^Wang, C.; Daimon, H.; Onodera, T.; Koda, T.; Sun, S. (2008). "A general approach to the size- and shape-controlled synthesis of platinum nanoparticles and their catalytic reduction of oxygen".Angewandte Chemie International Edition.47 (19):3588–91.doi:10.1002/anie.200800073.PMID18399516.
_NIST_ASD_emission_spectrum.png)
_Johns-Manville_Reef%2c_Stillwater_Complex.jpg)
platinum(II)-from-xtal-3D-balls-E.png)
![1,000 cubic centimeters of 99.9% pure platinum, worth about US$696,000 as of 29 Jun 2016 ($911,884 adjusted for inflation)[104]](/mt/?noimg=&dark=on&url=https%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aOne_litre_of_Platinum.jpg)
