Certain groups of ~ 2-5 atoms (functional groups) can give a molecule or material certain chemical properties, such as charge or reaction potential. The addition or modification of functional groups is known as functionalization. Common examples of functional goups in organic chemistry inlcude hydroxyl (-OH), carbonyl (-CNO), keto (>CO), carboxyl (-COOH), amino (-NH2), phosphate (-OPO3-2).
"...functionalising nanotubes (functionalising nanotubes (i.e. attaching things to nanotubes that change their properties)..." - TNTW 13, 2002
