CH3I\mathrm{CH}_{3} \mathrm{I}CH3I
CH3CH2Br \mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Br}CH3CH2Br
(CH3)2CHCH2I\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{I}(CH3)2CHCH2I
(CH3)3CBr\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CBr}(CH3)3CBr