Platinum

Platinum is a chemical element in the periodic table that has the symbol Pt and atomic number 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. more...

Platinum is used in jewellery, laboratory equipment, electrical contacts, dentistry, and automobile emissions control devices.

Notable characteristics

The metal appears silvery-white when pure, and firm. The metal is corrosion-resistant. The catalytic properties of the six platinum family metals are outstanding (a mixture of hydrogen and oxygen explodes in the presence of platinum). 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 jewelry. Platinum is more precious than gold. The price of platinum changes along with its availability, but it normally costs about twice as much as gold. In the 18th century, platinum's rarity made King Louis XV of France declare it the only metal fit for a king.

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. Platinum does not oxidise 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, +3, and +4.

Applications

• catalyst utilized in the catalytic converter, an optional component of the gasoline-fuelled automobile exhaust system (see "Notable characteristics" in this article),
• certain platinum-containing compounds are capable of intercalating into DNA and are chemotherapeutic agents owing to this capability. For example, cisplatin, carboplatin and oxaliplatin belong to this class of drugs,
• platinum resistance thermometers,
• electrodes for use in electrolysis.

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