Cyclononane Chemical compound Cyclononane is an alicyclic hydrocarbon consisting of a ring of nine carbon atoms. Its molecular formula is C9H18. References Cycloalkanes Cyclopropane Cyclobutane Cyclopentane Cyclohexane Cycloheptane Cyclooctane Cyclononane Cyclodecane Cycloundecane Cyclododecane Cyclotridecane Cyclotetradecane Cyclopentadecane Cyclohexadecane