Chemistry

An Overview about the Chemical Element Platinum



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Platinum

Symbol: Pt

Atomic Number: 78

Atomic Mass: 195.078 amu (atomic mass units)

Melting Point: 1772.0 C (2045.15 K, 3221.6 F)

Boiling Point: 3827.0 C (4100.15 K, 6920.6 F)

Number of Protons: 78

Number of Electrons: 78

Number of Neutrons: 117

Classification: Transition Metal

Crystal Structure: Cubic

Density @ 293 K: 21.45 grams per cubic centimeter

Color: silver

The discovery of platinum is credited to Antonio de Ulloa in 1735. However it was known to pre-Colombian Indians for some time. The Italian Julius Caesar Scaliger wrote about seeing a silver metal in Mexico in 1557. This metal was undoubtedly platinum and he described it as a noble metal "which no fire nor any Spanish artifice has yet been able to liquefy." The name platinum comes from "platina" which is the Spanish word for silver.

Platinum is one of the platinum group metals the other metals in this group are ruthenium, rhodium, palladium, osmium and iridium. It is a soft ductile metal that is highly resistant to corrosion.

There are six naturally occurring isotopes of platinum five of these are stable and the sixth, platinum-190 has an extremely long half-life. They are found in the following abundances: platinum-195 (33.832%), platinum-194 (32.967%), platinum-196 (25.242%), platinum-198 (7.163%), platinum-192 (0.782%) and platinum-190 (0.014%). Numerous unstable isotopes have been formed; they have mass numbers that range from 166 to 202.

Some platinum is found in its natural state in the gold bearing sands found in the Western United States, the Ural Mountains and in Columbia, South America. It is also found in the mineral ore cooperite which is mined in the Merensky Reef of South Africa. The platinum containing mineral sperrylite is found in the Sudbury basin area of Ontario in Canada. Recovery of platinum from sperrylite is a valuable by-product of the Sudbury nickel mining operation. The mineral deposits of the Sudbury basin have been associated with a large meteorite strike. Platinum is found in a higher concentration in the moon rocks from the Apollo missions and in meteorites than in any of earth's crustal rocks.

Platinum is a very expensive precious metal that that a number of uses.

* It is used to make jewelry.

* As platinum has a similar rate of heat expansion as soda-lime-silica glass it is used to make glass sealed electrodes.

* Platinum resistance wires are used in electric furnaces.

* Systems required to work at high temperatures for prolonged times are often coated with platinum. Such uses include missile nose cones and the fuel nozzles of jet engines.

Platinum is widely used as a catalyst in the following industrial applications

* Catalytic converters in motor vehicles convert carbon monoxide and any unburned fuel in exhaust fumes to carbon dioxide and water using oxygen from the air.

* The production of sulfuric acid.

* The cracking of petrochemicals.

* Fuel cells producing electrical energy from the combining of hydrogen and oxygen to from water.

* The change of methyl alcohol to formaldehyde with the production of heat. This reaction is used in small hand warming devices.

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