vananenud termin kahes tähenduses (kummagi kasutamine pole soovitatav): Alkeenide, eriti madalmolekulaarsete jaoks; Alkaandiüülrühmade, nt propaan-1,2-diüülrühma CH(CH3)CH2– puhul, An old term, which is not recommended, for alkenes, especially those of low molecular weight An old term for alkanediyl groups commonly but not necessarily having the free valencies on adjacent carbon atoms, e.g. CH(CH3)CH2– propylene (systematically called propane-1,2-diyl)