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��
Element radius (pm) | |
---|---|
H | 120 |
B | 208 |
C | 185 |
N | 154 |
O | 140 |
F | 135 |
Cl | 180 |
Br | 195 |
I | 215 |
He | 99 |
Reference
Housecroft. Inorganic Chemistry. 2008.