Single, Double and Triple Covalent Bonds
Simple Explanation
Atoms can share one pair of electrons (a single bond), two pairs (a double bond), or three pairs (a triple bond) — more shared pairs mean a stronger, shorter bond between the same two atoms.
Why Do We Need It?
The number of bonds between two atoms directly affects how strong and how reactive a molecule is — this is why nitrogen gas (N≡N, a triple bond) is so famously unreactive, while many double-bonded molecules readily take part in reactions.
Why Does This Work?
Each additional shared electron pair adds more attraction between the two positively charged nuclei and the negatively charged shared electrons packed between them, pulling the atoms closer together and requiring more energy to pull them apart — so bond order (single < double < triple) directly tracks with bond strength and inversely with bond length.
Real-Life Example
Why nitrogen gas is so stable
Nitrogen makes up about 78% of the air, and stays completely unreactive under normal conditions.
The two nitrogen atoms in N₂ are held together by a triple bond (three shared electron pairs) — one of the strongest bonds in chemistry — which is why enormous amounts of energy (like lightning, or industrial catalysts) are needed to break it apart for reactions such as fertilizer production.
Practice
Which bond is the strongest and shortest, all else being equal?
MediumCommon mistake
Assuming a double bond is simply "twice as strong" as a single bond in a precise numerical sense — bond order and bond strength are correlated, but the relationship is not a strict multiple; a double bond is stronger than a single bond, but generally less than exactly double.
Quick Review
- Single bond = 1 shared pair; double = 2 shared pairs; triple = 3 shared pairs.
- More shared pairs → shorter, stronger bonds.
- N₂'s triple bond is why nitrogen gas is so unreactive.