ElementsWhat is molybdenum?
Molybdenum is a silvery metal with one of the highest melting points of all elements. Plants and animals need a trace of it.
What is molybdenum used for?
Hard, heat-resistant steels for tools, engines and pipelines, catalysts in oil refining, and lubricants.
Where the name comes from
From the Greek word molybdos, lead, because its ore was confused with lead ore.
Key facts
- Symbol
- Mo
- Atomic number
- 42
- Atomic mass
- 95.95 u
- Family
- Transition metal
- Period
- 5
- Group
- 6
- Block
- d
- State at room temperature
- Solid
- Melting point
- 2,623 °C (2,896 K, 4,753 °F)
- Boiling point
- 4,639 °C (4,912 K, 8,382 °F)
- Density
- 10.2 g/cm³
- Electrons per shell
- 2, 8, 18, 13, 1
- Electron configuration
- [Kr]5s1 4d5
- Common oxidation states
- +6
- Electronegativity (Pauling)
- 2.16
- First ionisation energy
- 7.092 eV
- Electron affinity
- 0.746 eV
- Atomic radius (van der Waals)
- 209 pm
- Discovered
- 1778
Place in the periodic table
Molybdenum is element number 42. It sits in period 5 (row 5) of the periodic table, in group 6 (column 6), and belongs to the d-block. Just before it comes niobium (41), and just after it comes technetium (43). In the same column, chromium is above it and tungsten is below it. Elements in one column tend to behave alike.
Family: Transition metals.
Physical properties
At room temperature molybdenum is a solid. It melts at 2,623 °C and boils at 4,639 °C, so it stays liquid over a range of 2,016 degrees. Its density is 10.2 grams per cubic centimetre, so a one-litre block would weigh about 10.2 kilograms. By density it ranks 25th among the 96 elements with a measured value. It has the 6th highest melting point of all elements.
Inside the atom
An atom of molybdenum has 42 protons in its nucleus and, when neutral, 42 electrons around it. The electrons are arranged in 5 shells: 2, 8, 18, 13, 1. The outermost shell holds 1 electron. Written in full, the electron configuration is [Kr]5s1 4d5.
Its electronegativity on the Pauling scale is 2.16. 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 7.092 electronvolts (about 684 kilojoules per mole). One mole of molybdenum weighs 95.95 grams, so a single gram contains about 6.28 × 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 molybdenum 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.