Platinum Element Facts You Need to Know

Platinum is a transition metal that is highly valued for jewelry and alloys. There are many interesting facts about this element.

Platinum Basic Facts

• Atomic number: 78
• Symbol: Pt
• Atomic weight: 195.08

Discovery

It's difficult to assign credit for the discovery. Ulloa 1735 (in South America), Wood in 1741, Julius Scaliger in 1735 (Italy) can all make claims to this honor. Platinum was used in relatively pure form by the pre-Columbian Native Americans.

Electron configuration: [Xe] 4f¹⁴ 5d⁹ 6s¹

Word Origin

"Platinum" comes from the Spanish word platina, meaning "little silver."

Isotopes

Six stable isotopes of platinum occur in nature (190, 192, 194, 195, 196, 198). Information on three additional radioisotopes is available (191, 193, 197).

Properties

Platinum has a melting point of 1772 degrees C, the boiling point of 3827 +/- 100 degrees C, the specific gravity of 21.45 (20 degrees C), with a valence of 1, 2, 3, or 4. Platinum is a ductile and malleable silvery-white metal. It does not oxidize in air at any temperature, although it is corroded by cyanides, halogens, sulfur, and caustic alkalis. Platinum does not dissolve in hydrochloric or nitric acid but will dissolve when the two acids are mixed to form aqua regia.

Uses

Platinum is used in jewelry, wire, to make crucibles and vessels for laboratory work, electrical contacts, thermocouples, for coating items that must be exposed to high temperatures for long periods of time or must resist corrosion, and in dentistry. Platinum-cobalt alloys have interesting magnetic properties. Platinum absorbs large amounts of hydrogen at room temperature, yielding it at red heat. The metal is often used as a catalyst. The platinum wire will glow red-hot in the vapor of methanol, where it acts as a catalyst, converting it to formaldehyde. Hydrogen and oxygen will explode in the presence of platinum.

Where to Find It

Platinum occurs in native form, usually with small amounts of other metals belonging to the same group (osmium, iridium, ruthenium, palladium, and rhodium). Another source of the metal is sperrylite (PtAs₂).

Element Classification

Transition metal

Platinum Physical Data

• Density (g/cc): 21.45
• Melting point (K): 2045
• Boiling point (K): 4100
• Appearance: Very heavy, soft, silvery-white metal
• Atomic radius (pm): 139
• Atomic volume (cc/mol): 9.10
• Covalent radius (pm): 130
• Ionic radius: 65 (+4e) 80 (+2e)
• Specific heat (@20 degrees C J/g mol): 0.133
• Fusion heat (kJ/mol): 21.76
• Evaporation heat (kJ/mol): ~470
• Debye temperature (K): 230.00
• Pauling negativity number: 2.28
• First ionizing energy (kJ/mol): 868.1
• Oxidation states: 4, 2, 0
• Lattice structure: Face-Centered Cubic
• Lattice constant (Å): 3.920

Sources

Dean, John A. "Lange's Handbook of Chemistry." 15th Edition, McGraw-Hill Professional, October 30, 1998.

"Platinum." Periodic Table of Elements, Los Alamos National Laboratory, U.S. Department of Energy's NNSA, 2016.

Rumble, John. "CRC Handbook of Chemistry and Physics, 100th Edition." CRC Press, June 7, 2019.