Introduction to Platinum
Platinum is a chemical element represented by the symbol Pt and has an atomic number of 78. It is classified as a noble metal due to its exceptional resistance to corrosion and oxidation, even at high temperatures. This silvery-white, lustrous metal is highly dense, malleable, and ductile, meaning it can be hammered into thin sheets and drawn into fine wires without breaking. Platinum is one of the rarest elements in Earth’s crust, contributing to its high value and status as a precious metal.
Historical Understanding and Naming
Evidence suggests that platinum was used by pre-Columbian civilizations in South America, particularly in regions that are now Ecuador and Colombia, to create decorative objects and jewelry. These ancient artisans were likely working with naturally occurring alloys of platinum group metals.
The first European scientific mention of platinum is often attributed to Antonio de Ulloa, a Spanish scientist, who documented a metal he called “platina” (meaning “little silver” in Spanish) during his travels in South America in the 1730s. He noted its resistance to melting and its distinct properties compared to other known metals. The name “platinum” itself derives directly from this Spanish term, reflecting its resemblance to silver but its greater density and unique characteristics.
Key Characteristics and Applications
Here are five key facts about platinum:
- Rarity and Occurrence: Platinum is significantly rarer than gold, with its crustal abundance being only about 5 parts per billion. The largest known deposits are found in South Africa, which accounts for a substantial portion of global production, followed by Russia, Zimbabwe, Canada, and the United States.
- Exceptional Density: Platinum is one of the densest elements, with a density of 21.45 grams per cubic centimeter. This means a small volume of platinum will weigh considerably more than the same volume of many common materials, including lead.
- Catalytic Properties: One of platinum’s most crucial applications is its role as a catalyst. For instance, in automobile catalytic converters, platinum, along with palladium and rhodium, helps convert harmful pollutants in exhaust gases into less toxic substances like carbon dioxide, nitrogen, and water vapor. These devices are mandated in vehicles across many nations, including those in North America, Europe, and Asia.
- Resistance to Corrosion: Platinum does not oxidize in air at any temperature and is resistant to many common acids. This property makes it invaluable for laboratory equipment, such as crucibles and electrodes, which need to withstand harsh chemical environments, and for jewelry that requires lasting brilliance.
- Diverse Applications: Beyond catalytic converters and jewelry, platinum is used in various high-tech applications. These include medical implants (due to its biocompatibility), dental fillings, electrical contacts, temperature sensors, and in the production of hard disk drives, reflecting its versatility and unique physical and chemical properties.