What does nucleophilicity mean?
Nucleophilicity is a chemical term for the tendency of a molecule, ion, or functional group to act as a nucleophile: an electron-rich species that seeks and attacks an electrophilic site, such as the carbon atom bonded to a leaving group. The term is used to compare the reactive character of different electron donors and to help explain reaction rates, mechanisms, and product selectivity. A nucleophile can be described as having high or low nucleophilicity, but the comparison depends on factors such as solvent, molecular structure, and the identity of the electrophile. Nucleophilicity is not identical to basicity, although the two properties often correlate: basicity concerns the tendency to accept a proton, while nucleophilicity concerns the ability and rate of bond-forming attack. The word is especially common in organic chemistry, mechanistic studies, catalysis, and the design of synthetic reactions.
nounNucleophilicity is the tendency or ability of a chemical species, called a nucleophile, to attack an electrophilic site and form a new chemical bond. In organic chemistry, it is commonly used to describe the strength of a nucleophile and to help predict reaction rates and selectivity.
- The tendency or ability of a chemical species to act as a nucleophile by attacking an electrophilic centre and forming a new bond.
"The reaction conditions were chosen to increase the nucleophilicity of the alkoxide ion."
"Stronger electron-donating groups can increase the nucleophilicity of an aniline derivative."
"The researchers used a quantitative measure of nucleophilicity to compare several catalysts."
The plural is uncommon because nucleophilicity is usually treated as an uncountable abstract property.
"The study compared the nucleophilicities of several catalyst intermediates."
The more nucleophilic a species is, the more readily it seeks out an electrophilic partner—but solvent, structure, and competing reactions can change the outcome.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of nucleophilicity
Nucleophilicity is formed from nucleophile by adding the suffix -ity, which turns a noun or adjective into an abstract quality noun. Nucleophile combines a derivative of Latin nucleus, meaning “kernel” or “nut,” with the Greek suffix -phile, meaning “loving” or “favouring.” The related adjectives nucleophilic and nuclear reflect the same Latin root, while the terminology ultimately distinguishes the electron-rich centre from the nucleus of an atom.
Related word forms
How nucleophilicity is actually used
This is primarily a technical term in organic and physical chemistry. It describes a chemical species or site rather than a complete reaction, and comparisons are meaningful only when the solvent and other reaction conditions are controlled.
Easily confused with nucleophilicity
A nucleophile is the chemical species that attacks an electrophile, whereas nucleophilicity is the property describing how strongly or readily it does so.