Organic Chemistry Functional Groups

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Hydrocarbons Alkanes: Contains only C-C single bonds. General formula: $C_nH_{2n+2}$. Example: Ethane ($CH_3CH_3$) Alkenes: Contains at least one C=C double bond. General formula: $C_nH_{2n}$. Example: Ethene ($CH_2=CH_2$) Alkynes: Contains at least one C$\equiv$C triple bond. General formula: $C_nH_{2n-2}$. Example: Ethyne ($CH\equiv CH$) Arenes (Aromatic): Cyclic, planar, conjugated system of $\pi$ electrons (e.g., Benzene). Example: Benzene ($C_6H_6$) Containing Oxygen Alcohols: Hydroxyl group (-OH) attached to an alkyl group. Structure: $R-OH$ Example: Ethanol ($CH_3CH_2OH$) Ethers: Oxygen atom bonded to two alkyl or aryl groups. Structure: $R-O-R'$ Example: Diethyl ether ($CH_3CH_2OCH_2CH_3$) Aldehydes: Carbonyl group ($C=O$) where carbon is bonded to at least one hydrogen and one alkyl/aryl group. Structure: $R-CHO$ Example: Ethanal ($CH_3CHO$) Ketones: Carbonyl group ($C=O$) where carbon is bonded to two alkyl or aryl groups. Structure: $R-CO-R'$ Example: Propanone ($CH_3COCH_3$) Carboxylic Acids: Carboxyl group (-COOH). Structure: $R-COOH$ Example: Ethanoic acid ($CH_3COOH$) Esters: Carboxyl group where -OH is replaced by -OR'. Structure: $R-COO-R'$ Example: Ethyl ethanoate ($CH_3COOCH_2CH_3$) Containing Nitrogen Amines: Derivatives of ammonia ($NH_3$) where one or more H atoms are replaced by alkyl/aryl groups. Primary Amine: $R-NH_2$ Secondary Amine: $R_2NH$ Tertiary Amine: $R_3N$ Example: Methylamine ($CH_3NH_2$) Amides: Carboxyl group where -OH is replaced by -NH2, -NHR, or -$NR_2$. Structure: $R-CO-NR'_2$ (where $R'$ can be H or alkyl) Example: Ethanamide ($CH_3CONH_2$) Nitriles: Contains a cyano group ($C\equiv N$). Structure: $R-C\equiv N$ Example: Ethanenitrile ($CH_3C\equiv N$) Containing Sulfur Thiols (Mercaptans): Sulfur analogue of alcohols, contains a sulfhydryl group (-SH). Structure: $R-SH$ Example: Ethanethiol ($CH_3CH_2SH$) Thioethers (Sulfides): Sulfur analogue of ethers, contains $R-S-R'$. Structure: $R-S-R'$ Example: Dimethyl sulfide ($CH_3SCH_3$) Sulfonic Acids: Contains a sulfo group ($-SO_3H$). Structure: $R-SO_3H$ Example: Benzenesulfonic acid ($C_6H_5SO_3H$) Containing Halogens Alkyl Halides (Haloalkanes): Halogen atom (F, Cl, Br, I) attached to an alkyl group. Structure: $R-X$ (where $X = F, Cl, Br, I$) Example: Chloroethane ($CH_3CH_2Cl$) Acyl Halides: Carboxyl group where -OH is replaced by a halogen atom. Structure: $R-CO-X$ Example: Ethanoyl chloride ($CH_3COCl$) Other Important Groups Anhydrides: Two acyl groups joined by an oxygen atom. Structure: $(RCO)_2O$ Example: Ethanoic anhydride ($(CH_3CO)_2O$) Phosphates: Contains a phosphate group (e.g., $R-O-PO_3^{2-}$). Example: Methyl phosphate ($CH_3OPO_3^{2-}$) Summary Table of Common Functional Groups Class Functional Group General Formula Suffix/Prefix Alkane C-C (single bond) $R-H$ -ane Alkene C=C (double bond) $R_2C=CR_2$ -ene Alkyne C$\equiv$C (triple bond) $R-C\equiv C-R'$ -yne Alcohol -OH (hydroxyl) $R-OH$ -ol / hydroxy- Ether -O- (ether) $R-O-R'$ -ether / alkoxy- Aldehyde -CHO (carbonyl at end) $R-CHO$ -al / formyl- Ketone -CO- (carbonyl in middle) $R-CO-R'$ -one / oxo- Carboxylic Acid -COOH (carboxyl) $R-COOH$ -oic acid / carboxy- Ester -COO- (ester) $R-COO-R'$ -oate / alkoxycarbonyl- Amine -NH$_2$, -NHR, -$NR_2$ (amino) $R-NH_2$ -amine / amino- Amide -CONH$_2$ (carboxamide) $R-CONR'_2$ -amide / carbamoyl- Nitrile -C$\equiv$N (cyano) $R-C\equiv N$ -nitrile / cyano- Thiol -SH (sulfhydryl) $R-SH$ -thiol / mercapto- Alkyl Halide -X (halo) $R-X$ halo-