Platinum [Pt]

Characteristics

An: 78 N: 117
Am: 195.078 g/mol
Group No: 10

Group Name: Precious metal or platinum group metal
Block: d-block Period: 6
State: solid at 298 K
Colour: greyish white Classification: Metallic
Boiling Point: 4098K (3825°C)
Melting Point: 2041.4K (1768.3°C)
Critical temperature: 0K (0°C)
Superconducting temperature: 0K (0°C)

Density: 21.45g/cm³

Discovery Information

Who: Antonio de Ulloa and Don Jorge Juan y Santacilia
When: 1734
Where: Peru

Name Origin

Spanish: platina (little silver).
"Platinum" in different languages.

Sources

Produced from ores called native platinum. Primary producers are Russia, Canada, South Africa, Colombia and Peru. Annual production is around 30 tons.

A rod of solid platinum weighing 21 troy ounces. At July 2006 prices this rod is worth around US$25,500.

Abundance

Universe: 0.005 ppm (by weight)
Sun: 0.009 ppm (by weight)
Carbonaceous meteorite: 0.1 ppm
Earth’s Crust: 0.0037 ppm
Seawater: Atlantic surface: n/a ppm; Atlantic deep: n/a ppm; Pacific surface: 1.1 x 10^-7 ppm; Pacific deep: 2.7 x 10^-7 ppm

Uses

Used in jewellery, to make crucibles, special containers, as a catalyst (in catalytic converters fixed to cars), in dental crowns, as an anti-tumor agent and to make standard weights and measures. It is also combined with cobalt to produce very strong magnets.

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 Darien (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. Among 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.

Notes

Discovered by astronomer Antonio de Ulloa and Don Jorge Juan y Santacilia during a geographical expedition in Peru that lasted from 1735 to 1745. Ulloa observed 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. It is thought that Charles Wood independently isolated the element in 1741.
The Italian humanist Julius Caesar Scaliger makes the first European reference to Platinum in 1557, as a description of a mysterious metal found in Central American mines between Darien (Panama) and Mexico.
Platinum is considered a precious metal and is traded on the world’s commodities exchanges, it’s price fluctuates with availability, but is usually around twice that of gold.

Platinum Compounds

Oxaliplatin C₈H₁₂N₂O₄Pt : A platinum-based chemotherapy drug.

Reactions of Platinum

Reactions with air
Platinum metal does not normally react with air or oxygen.

Reactions with halogens
Careful control of the reaction between platinum metal and fluorine gas results in either the volatile platinum(VI) fluoride, PtF6 or the tetrameric platinum(V) fluoride, (PtF₅)₄. The latter posseses the same type of structure as (IrF₅)₄, (RhF₅)₄, (OsF₅)₄, and (RuF₅)₄, and disproportionates into platinum(VI) fluoride and platinum(IV) fluoride.

Pt_(s) + 3F_2(g) --> PtF_6(s)
4Pt_(s) + 10F_2(g) --> (PtF₅)_4(s)
(PtF₅)_4(s) + PtF_6(g) --> PtF_4(s)

Tetrachloride, tetrabromide and tetraiodide are formed in the reactions of platinum metal and the respective halogens.

Pt_(s) + 2Cl_2(g) --> PtCl_4(s)
Pt_(s) + 2Br_2(g) --> PtBr_4(s)
Pt_(s) + 2I_2(g) --> PtI_4(s)

Platinum(II) chloride is also formed in the controlled reaction of platinum metal and chlorine. Depending upon the reaction conditions, one of two different forms of PtCl₂ is formed.

Pt_(s) + Cl_2(g) --> PtCl_2(s)

Occurrence of Platinum

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, Canada and Botswana, reports the British Geological Survey.
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 western 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.

Isotopes of Platinum

¹⁹⁰Pt [112 neutrons]
Abundance: 0.01%
Half life: 6.5 x 10¹¹ years [ Alpha Decay ]
Decay Energy: 3.18 MeV
Decays to ¹⁸⁶Os.

¹⁹¹Pt [113 neutrons]
Abundance: synthetic
Half life: 2.96 days [ Electron Capture ]
Decay Energy: ? MeV
Decays to ¹⁹¹Ir.

¹⁹²Pt [114 neutrons]
Abundance: 0.79%
Stable wiht 114 neutrons

¹⁹³Pt [115 neutrons]
Abundance: synthetic
Half life: 4.33 days
Decay Energy: 0.1355 MeV
Decays to ¹⁹³Pt.

¹⁹³Pt [115 neutrons]
Abundance: synthetic
Half life: 50 years [ Electron Capture ]
Decay Energy: ? MeV
Decays to ¹⁹³Ir.

¹⁹⁴Pt [116 neutrons]
Abundance: 32.9%
Stable with 116 neutrons

^195mPt [117 neutrons]
Abundance: synthetic
Half life: 4.02 days
Decay Energy: 0.1297 MeV
Decays to 195Pt.

¹⁹⁵Pt [117 neutrons]
Abundance: 33.8%
Stable with 117 neutrons

¹⁹⁶Pt [118 neutrons]
Abundance: 25.3%
Stable with 118 neutrons

^197mPt [119 neutrons]
Abundance: synthetic
Half life: 1.59 hours
Decay Energy: 0.3456 MeV
Decays to ¹⁹⁷Pt.

¹⁹⁷Pt [119 neutrons]
Abundance: synthetic
Half life: 19.8913 hours [ beta- ]
Decay Energy: 0.719 MeV
Decays to ¹⁹⁷Au.

¹⁹⁸Pt [120 neutrons]
Abundance: 7.2%
Stable with 120 neutrons

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