CH3COOH\mathrm{CH}_{3} \mathrm{COOH}CH3COOH
CH2CI−COOH\mathrm{CH}_{2} \mathrm{CI}-\mathrm{COOH}CH2CI−COOH
CHCI2−COOH\mathrm{CHCI}_{2}-\mathrm{COOH}CHCI2−COOH
CCl3−COOH\mathrm{CCl}_{3}-\mathrm{COOH}CCl3−COOH