AllChemicals — The Online Chemical Glossary | https://allchemicals.info/chemical/611-nucleophile
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Quick Reference
Also Known As
Nucleophilic reagent, Lewis base (related), electron donor, Nu:
What is Nucleophile?
An electron-rich species that donates electrons to an electrophile in a chemical reaction. Nucleophiles attack electron-poor carbon atoms in substitution and addition reactions. Examples include OH⁻, CN⁻, NH₃, halide ions, and water. Nucleophilicity relates to electron availability.
Properties & Characteristics
A nucleophile (from Greek: nucleus-loving) is an electron-rich species that donates an electron pair to an electrophile (electron-poor species) in a chemical reaction. Nucleophiles can be: anionic (OH⁻, Cl⁻, CN⁻, RS⁻, H⁻, RNH₂ acting as anions), or neutral (H₂O, NH₃, R₃P, CO). Nucleophilicity depends on: charge (anions > neutral), polarisability (heavier atoms are better nucleophiles in polar aprotic solvents — I⁻ > Br⁻ > Cl⁻ > F⁻), and solvent effects.
Uses & Applications
Nucleophiles are central to: SN2 reactions (backside attack), SN1 reactions (carbocation capture), addition to carbonyl groups (nucleophilic addition), Michael additions (1,4-addition of nucleophiles to enones), and biochemical reactions (enzyme active site nucleophiles, such as serine OH in serine proteases, or cysteine SH in cysteine proteases).
Safety Information
Strong nucleophiles (cyanide CN⁻, organolithiums, Grignard reagents) are acutely toxic or dangerously reactive. CN⁻ is lethal. Organolithiums are pyrophoric and react violently with water and air. Handle all strongly nucleophilic reagents with appropriate inert atmosphere and safety measures.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
SynonymsNucleophilic reagent, Lewis base (related), electron donor, Nu:
Frequently Asked Questions
An electron-rich species that donates electrons to an electrophile in a chemical reaction. Nucleophiles attack electron-poor carbon atoms in substitution and addition reactions. Examples include OH⁻, CN⁻, NH₃, halide ions, and water. Nucleophilicity relates to electron availability.
Nucleophiles are central to: SN2 reactions (backside attack), SN1 reactions (carbocation capture), addition to carbonyl groups (nucleophilic addition), Michael additions (1,4-addition of nucleophiles to enones), and biochemical reactions (enzyme active site nucleophiles, such as serine OH in serine …
Strong nucleophiles (cyanide CN⁻, organolithiums, Grignard reagents) are acutely toxic or dangerously reactive. CN⁻ is lethal. Organolithiums are pyrophoric and react violently with water and air. Handle all strongly nucleophilic reagents with appropriate inert atmosphere and safety measures.
Editorial standards: Chemical data is sourced from peer-reviewed literature,
CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA,
and IAEA. For educational purposes only — always consult official SDS documentation and qualified
professionals before handling chemicals.
