N'ihe banyere kemịkalụ, isomer bụ ion maọbụ molekụla nwere otu usoro mana ha nwere ihe owuwu dị iche. Isomer anaghị enwe ihe ndị yiri ya. Ụdị abụọ nke isomerism bụ isomerism structural (ma ọ bụ constitutional isomerism) na stereoisomerism (ma ọ bụ isomerism spatial). Ajụjụ: Gịnị bụ ụdị isi nke isomerism a maara dị ka?
structural isomerism (ma ọ bụ constitutional isomerism) na stereoisomerism (ma ọ bụ spatial isomerism)