C6H5CN\mathrm{C}_{\mathrm{6}} \mathrm{H}_{5} \mathrm{CN}C6H5CN
CH3I\mathrm{CH}_{3} \mathrm{I}CH3I
(C6H5)2C=O\left(\mathrm{C}_{6} \mathrm{H}_{5}\right)_{2} \mathrm{C}=O(C6H5)2C=O
RCOC \text { RCOC } RCOC