Cl3C−CHO\mathrm{Cl}_{3} \mathrm{C}-\mathrm{CHO}Cl3C−CHO
H−CHO\mathrm{H}-\mathrm{CHO}H−CHO
CH3CH2CHO\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CHO}CH3CH2CHO
C6H5CHO\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}C6H5CHO