(CH3)3C−CHO\left(\mathrm{CH}_{3}\right)_{3} \mathrm{C}-\mathrm{CHO}(CH3)3C−CHO
HCHO \text { HCHO } HCHO
C6H5CHO\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}C6H5CHO
CH3CHO\mathrm{CH}_{3} \mathrm{CHO}CH3CHO