H−CHO\mathrm{H}-\mathrm{CHO}H−CHO
CH3−CHO\mathrm{CH}_{3}-\mathrm{CHO}CH3−CHO
CH3−CH2−CHO\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CHO}CH3−CH2−CHO
CH3−CO−CH3\mathrm{CH}_{3}-\mathrm{CO}-\mathrm{CH}_{3}CH3−CO−CH3