HCHO\mathrm{HCHO}HCHO
C6H5CHO\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}C6H5CHO
(CH3)3CCHO\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCHO}(CH3)3CCHO
CH3CHO\mathrm{CH}_{3} \mathrm{CHO}CH3CHO
Cl3CCHO\mathrm{Cl}_{3} \mathrm{CCHO}Cl3CCHO