CH3CH2COOH\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{COOH}CH3CH2COOH
CICH2CH2COOH\mathrm{CICH}_{2} \mathrm{CH}_{2} \mathrm{COOH}CICH2CH2COOH
CI2CHCOOH\mathrm{CI}_{2} \mathrm{CHCOOH}CI2CHCOOH
CH3COOH\mathrm{CH}_{3} \mathrm{COOH}CH3COOH