double bond
C1/C2Academic, Scientific, Technical
Definition
Meaning
A chemical bond between two atoms involving the sharing of two pairs of electrons (four electrons total).
A strong covalent bond that is less flexible than a single bond, restricting rotation and giving rise to geometric (cis/trans) isomerism in organic molecules like alkenes. In a broader conceptual sense, it can metaphorically represent a strong, rigid connection or commitment.
Linguistics
Semantic Notes
The term is almost exclusively used in chemistry. Its meaning is precise and technical, with little semantic drift. It contrasts directly with 'single bond' and 'triple bond'.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Spelling conventions (e.g., 'behaviour' vs. 'behavior' in surrounding text) may apply.
Connotations
None beyond the strict scientific definition.
Frequency
Equally frequent and essential in the scientific discourse of both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
The molecule HAS a double bond BETWEEN atom X and atom Y.A double bond IS FORMED.The double bond WAS BROKEN/HYDROGENATED.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “[None - term is purely technical]”
Usage
Context Usage
Business
Virtually never used.
Academic
Core terminology in chemistry, biochemistry, and materials science lectures, textbooks, and research papers.
Everyday
Extremely rare, only in educational contexts or popular science.
Technical
The primary register. Used in lab reports, chemical engineering, pharmaceutical research, and patent applications.
Examples
By Part of Speech
verb
British English
- The catalyst helps to hydrogenate, or add hydrogen across, the double bond.
- The compound can isomerise, moving the double bond along the carbon chain.
American English
- The reaction mechanism involves attacking the double bond.
- We need to reduce the double bond to form the saturated product.
adverb
British English
- [No standard adverbial use]
American English
- [No standard adverbial use]
adjective
British English
- The double-bond character of the linkage affects its length.
- They studied the double-bond isomerisation process.
American English
- The double-bond energy is higher than that of a single bond.
- This is a classic double-bond addition reaction.
Examples
By CEFR Level
- [Not typically taught at this level]
- Ethene is a simple gas with a carbon-carbon double bond.
- A double bond is stronger and shorter than a single bond.
- The presence of a double bond makes alkenes more reactive than alkanes.
- Geometric isomerism is possible because rotation around a double bond is restricted.
- The polymerisation reaction involves the opening of the carbon-carbon double bonds in the monomer units.
- Spectroscopic analysis confirmed the conjugation of the double bond system within the aromatic ring.
Learning
Memory Aids
Mnemonic
Think of a double date: two pairs (of electrons) sharing an experience, making the connection stronger and less likely to change plans (rotate) than a single date (single bond).
Conceptual Metaphor
A DOUBLE BOND IS A RIGID CONNECTION / A DOUBLE BOND IS A SITE OF REACTIVITY.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Direct translation 'двойная связь' is accurate and poses no trap.
- The conceptual trap is assuming it's simply 'twice as strong' as a single bond; it's a different type of bond with distinct chemical and physical properties.
Common Mistakes
- Pronouncing 'bond' like the fictional spy 'James Bond' (/bɒnd/ in UK, /bɑːnd/ in US is correct).
- Using 'double bond' to describe a strong emotional connection (incorrect metaphorical extension).
- Confusing it with 'double bind' (a psychological dilemma).
Practice
Quiz
What is the primary chemical consequence of a double bond in an organic molecule?
FAQ
Frequently Asked Questions
No. A double bond consists of one sigma (σ) bond and one pi (π) bond. The pi bond has a different electron distribution and is responsible for the bond's rigidity and characteristic reactivity.
Yes, abundantly. They are crucial in biological molecules. For example, unsaturated fats contain double bonds, and the colour of carotenoids in carrots is due to conjugated double bond systems.
A 'double bond' is a chemistry term. A 'double bind' is a psychological term for a no-win situation where contradictory messages are received.
In benzene, the six pi electrons from its double bonds are delocalised in a ring above and below the plane of the carbon atoms. This delocalisation (aromaticity) makes benzene exceptionally stable and its bonds of equal length, intermediate between single and double bonds.