Bond Length
The equilibrium distance between the nuclei of two bonded atoms.
Formula / equation
d ≈ r₁ + r₂
Unit
pm
In depth
Bond length is set by the balance between attraction of each nucleus for the shared electrons and the mutual repulsion of the nuclei. It shortens as bond order increases and as the bonded atoms get smaller, and it correlates inversely with bond strength across almost all series.
Examples in the real world
C–C is 154 pm, C=C 134 pm and C≡C 120 pm; H–F is 92 pm while H–I is 161 pm.