ElementsWhat is platinum?
Platinum is a dense, silvery-white precious metal that does not tarnish. It is rarer than gold.
What is platinum used for?
Catalytic converters, jewellery, laboratory ware, some cancer medicines, and catalysts in fuel cells and the chemical industry.
Where the name comes from
From the Spanish word platina, 'little silver'.
Key facts
- Symbol
- Pt
- Atomic number
- 78
- Atomic mass
- 195.08 u
- Family
- Transition metal
- Period
- 6
- Group
- 10
- Block
- d
- State at room temperature
- Solid
- Melting point
- 1,768 °C (2,042 K, 3,215 °F)
- Boiling point
- 3,825 °C (4,098 K, 6,917 °F)
- Density
- 21.46 g/cm³
- Electrons per shell
- 2, 8, 18, 32, 17, 1
- Electron configuration
- [Xe]6s1 4f14 5d9
- Common oxidation states
- +4, +2
- Electronegativity (Pauling)
- 2.28
- First ionisation energy
- 9 eV
- Electron affinity
- 2.128 eV
- Atomic radius (van der Waals)
- 209 pm
- Discovered
- 1735
Place in the periodic table
Platinum is element number 78. It sits in period 6 (row 6) of the periodic table, in group 10 (column 10), and belongs to the d-block. Just before it comes iridium (77), and just after it comes gold (79). In the same column, palladium is above it and darmstadtium is below it. Elements in one column tend to behave alike.
Family: Transition metals.
Physical properties
At room temperature platinum is a solid. It melts at 1,768 °C and boils at 3,825 °C, so it stays liquid over a range of 2,056 degrees. Its density is 21.46 grams per cubic centimetre, so a one-litre block would weigh about 21.46 kilograms. By density it ranks 3rd among the 96 elements with a measured value.
Inside the atom
An atom of platinum has 78 protons in its nucleus and, when neutral, 78 electrons around it. The electrons are arranged in 6 shells: 2, 8, 18, 32, 17, 1. The outermost shell holds 1 electron. Written in full, the electron configuration is [Xe]6s1 4f14 5d9.
Its electronegativity on the Pauling scale is 2.28. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 9 electronvolts (about 868 kilojoules per mole). One mole of platinum weighs 195.08 grams, so a single gram contains about 3.09 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains platinum with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.