CH3CHO\mathrm{CH}_{3} \mathrm{CHO}CH3CHO
HCHO\mathrm{HCHO}HCHO
CH3COCH3\mathrm{CH}_{3} \mathrm{COCH}_{3}CH3COCH3
C6H5CHO\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}C6H5CHO