Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Platinum is one of the least reactive metals. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequently, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the alluvial sands of various rivers, it was first used by pre-Columbian South American natives to produce artifacts.
Platinum is a lustrous, silver-white metal that is more ductile than gold, silver, or copper but less malleable than gold. It has excellent resistance to corrosion and does not oxidize in air, making it useful for industrial applications and fine jewelry. Common oxidation states are +2 and +4; it reacts with some halogens and sulfur but is generally unreactive. It dissolves in hot aqua regia to form chloroplatinic acid. Platinum is significant in catalytic converters, as evidenced by the 2007 Nobel Prize in Chemistry awarded for research on its catalytic properties.
Oxidation states +2 and +4
Nobel Prize in catalysis
Platinum is primarily used in catalytic converters, accounting for about 50% of annual demand. It’s also used as a catalyst in the chemical industry for producing nitric acid, silicone, and benzene, as well as in fuel cells. In electronics, it’s used for computer hard disks and thermocouples. Additional applications include optical fibers, LCDs, turbine blades, spark plugs, pacemakers, and dental fillings. Platinum compounds are important in chemotherapy for cancer treatment.
1,769 °C (3,216 °F)
3,827 °C (6,920 °F)
21.45 (20 °C)