Van der Waals Radius Definition

What Is the Van der Waals Radius in Chemistry?

The van der Waals radius is half the distance between two nonbonded atoms at their closest approach.
The van der Waals radius is half the distance between two nonbonded atoms at their closest approach. Stanislaw Pytel / Getty Images

The Van der Waals radius is equal to one half the distance between two unbonded atoms when the electrostatic forces between them are balanced. In other words, it is half of the closest distance between two atoms that aren't bonded or within the same molecule. Picometers (pm) are typically the unit used to report the value.

The distance reflects the action of intermolecular forces (e.g., dipole-dipole and dispersion forces) and is related to van der Waals interactions.

Knowing the van der Waals radius is helpful when predicting how closely atoms will pack to form a solid.

Sample Van der Waals Radius Values

ElementRadius (pm)
H120
B208
C185
N154
O140
F135
Cl180
Br195
I215
He99

Reference

  • Housecroft. Inorganic Chemistry. 2008.