substituent
/səbˈstɪtjʊənt
/noun Chemistry
An atom or group of atoms taking the place of another atom or group or occupying a specified position in a molecule: displacement of alkyl substituents [as modifier]: the presence of substituent hydrogen atoms...
- In an interstitial solid solution, substituent atoms or ions are added to void spaces (interstitial sites) between normal atomic sites.
- Under rigorous conditions benzene will undergo substitution for one of its hydrogen substituents, by a process called electrophilic aromatic substitution.
- Any groups attached to the main chain are called substituents, they are there in place of hydrogen atoms.
Origin
Late 19th century: from Latin substituent- 'standing in place of', from the verb substituere (see substitute).