Bond Order Calculator
Calculate the bond order of a molecule from molecular orbital theory. Enter the number of bonding and antibonding electrons to get the bond order and a quick read on bond stability.
Formula
Bond Order = (Bonding Electrons − Antibonding Electrons) ÷ 2
- Bond order = (bonding electrons − antibonding electrons) ÷ 2, from molecular orbital (MO) theory.
- Count electrons in bonding MOs and subtract those in antibonding (starred) MOs.
- A bond order of 1, 2, or 3 corresponds to a single, double, or triple bond; fractional values are possible.
- A bond order of 0 means no net bond — the molecule is not expected to exist (e.g. Ne₂).
- Higher bond order generally means a shorter, stronger bond.
O₂: 8 bonding, 4 antibonding electrons
Inputs
- Bonding Electrons: 8
- Antibonding Electrons: 4
Bond order = (8 − 4) ÷ 2 = 2, a double bond, consistent with O₂.
Frequently asked questions
What is bond order?
Bond order is the number of chemical bonds between a pair of atoms, calculated from the difference between bonding and antibonding electrons.
How do I count bonding and antibonding electrons?
Fill the molecular orbital diagram for the molecule, then total the electrons in bonding orbitals and in antibonding (starred) orbitals separately.
What does a higher bond order mean?
A higher bond order indicates a stronger, shorter bond — a triple bond is stronger than a double, which is stronger than a single.
Can bond order be a fraction?
Yes. Species like O₂⁻ or NO have odd electron counts and end up with fractional bond orders such as 1.5 or 2.5.
What does a bond order of zero mean?
It means there is no net bonding, so the molecule is predicted not to form — for example, He₂ or Ne₂.