Discovered | Name | Characteristics | Found | Uses

Platinum is a transition metal in Group VIIIB (Group 10) and the 6th period. Other members of the group are nickel (Ni) and palladium (Pd).

Discovered in South America in 1735 by Ulloa. Name derived from the Spanish word platina for silver.

Platinum is a nonreactive, silvery metal that has a very high melting point (1769°C) for a metal. In the solid state, the metal has a face-centered cubic structure.

About as abundant in the earth's crust as gold.

The sands of the rivers along the west coast of South America are rich in gold, and platinum is often found along with it. It is not surprising that the natives of this continent for centuries used the elements to make ornaments. When the Spanish explored Central and South America beginning in the 16th century, they found native treasures made of platinum and gave the metal its name from the word platina, which means "little silver" in Spanish and which tells us that the metal looks more like silver than gold.

The Spanish explorers were much more interested in gold than platinum. In fact, when they found platinum in the rivers along with gold, they believed at first that the platinum was gold that had not been buried long enough to ripen into gold, and they threw the platinum back into the rivers!

Platinum did not find its way to Europe until the 18th century. In 1736 a Spanish naval officer, de Ulloa, observed platinum in the gold mines of South America. On his way back to Spain in 1745, however, his ship was attacked by privateers and eventually captured by the British navy. He and his papers describing platinum were taken to London where members of the Royal Society became aware of his work and actually elected him a member of the Society.

Because of its color, beauty, and value, platinum was known as "white gold" by its early European discoverers. However, it soon became apparent that it was much more difficult to work with than gold, in part because the melting point of platinum (1769°C) is so much higher than those of other metals. Many attempts were made to melt platinum, but the French chemist Lavoisier was apparently the first to achieve the feat on a small scale in 1782. It was not until late in the last century that larger amounts could be melted and that it became possible to work platinum metal into useful products.

Platinum, which is about as abundant as gold in the earth's crust, is usually found with other metals of the "platinum group": ruthenium and osmium, rhodium and iridium, and palladium. Until about 1820 all platinum came from South America, but then deposits were discovered in Russia and later in South Africa. The greatest amount now comes from the mines of South Africa. Mining the metal is quite a feat: roughly 10 tons of rocks must be removed to isolate 1 troy ounce (31.1 grams).

Consumption of platinum in the United States is annually about 1,300,000 troy ounces or about 45,000 tons. Most, by far, is used in emission control catalysts in automobiles, but the next most important use is in the chemical industry. In 1988 approximately 34 billion pounds of nitric acid were produced in the United States in a process that relies on the use of platinum as a catalyst to accelerate a crucial step in the process.

Since platinum conducts electricity, has a high melting point and is not easily corroded, it is used to make wire, laboratory ware and vessels for high temperature processes. For example, glass fibers are made by forcing molten glass through many small holes in a sheet of platinum.

Platinum and the metals to which it is related have an extraordinarily rich and interesting chemistry. Many of their compounds act as catalysts for chemical reactions, but the newest and most exciting use of a platinum-containing compound is the cancer chemotherapy agent cisplatin, (NH3)2PtCl2.