Identifying Functional Groups
A functional group is a group of atoms with specific physical, chemical, and reactivity properties. Functional groups in organic chemistry are important for many future topics, including their predictable characteristics, nomenclature, reactivity, synthesis, spectroscopy, and more. The main functional groups are often identified by their stoichiometry, which is the relative quantities of atoms in the formula of the group.
There are 19 main organic functional groups:
- An alkane is a hydrocarbon containing only single bonds and hydrogen with CnH2n+2 stoichiometry.
- An alkene is a hydrocarbon containing at least one carbon-carbon double bond () with CnH2n stoichiometry.
- An alkyne is a hydrocarbon that contains at least one carbon-carbon triple bond () with CnH2n-2 stoichiometry.
- An alkyl halide is an organic compound that contains a halogen atom. The halogen atom can be classified as primary, secondary, tertiary, vinylic, or aromatic.
- An alcohol is a hydrocarbon containing a hydroxyl functional group ().
- An ether is an organic molecule containing an oxygen bound by two alkyl or aryl groups through bonds ().
- A thiol is an organic compound that is derived from H2S. It contains an alkyl or aryl group covalently linked to a sulfhydryl group, , through bonds, with stoichiometry.
- A sulfide is an organic molecule containing a sulfur bonded to two alkyl or aryl groups through bonds.
- An aromatic is an uninterrupted planar ring of sp2 and/or p orbitals whose electron count adds up to where any positive integer. Benzene, C6H6, is the most common example.
- A ketone is an organic compound that contains a carbonyl group () bound to two alkyl () fragments (which can be the same, R and R, or different, R and R′) with or RCOR′ stoichiometry.
- An aldehyde is an organic compound that contains a carbonyl group () bound to one alkyl () fragment and one hydrogen atom, with or stoichiometry.
- A carboxylic acid is a compound that contains an alkyl or aryl group (R) attached to a carboxyl group ().
- An ester is an organic compound that contains a carboxyl unit in which a hydrogen of the hydroxyl group is replaced by an alkyl or aryl group, giving it or stoichiometry.
- An acyl halide is an organic compound that contains a carbonyl group () bound to one alkyl () fragment and one halogen atom, with or stoichiometry.
- An acid anhydride is an organic compound that contains two carbonyl groups () bound to the same oxygen atom with (RCO)2O stoichiometry.
- An amide is an organic compound that contains a carbonyl () linked to nitrogen atoms through a bond. It has a general stoichiometry.
- An amine is an organic compound that is a derivative of ammonia (NH3), where one or more hydrogen atoms are replaced by alkyl or aryl units (R), forming single bonds.
- A nitrile is an organic compound that has a carbon triple bonded to a nitrogen with RCN stoichiometry.
- An epoxide is a compound that contains a cyclic ether made of two carbons and an oxygen.
- An aryl is the term that applies when a group is attached to an aromatic compound; is an aryl bromide.
In organic chemistry, R is the abbreviation for any alkyl group. So, R can be , , and so on. To indicate there are different alkyl groups, a prime (′) or double prime (″) symbol is used. Alternately, R1 or R2 is used to indicate different alkyl groups. For example, an ether with different alkyl groups may be abbreviated with either or .
Organic Functional Groups
|Functional Group Name||Abbreviation||General Structure|
|Nitrile (also called cyano)|
Functional groups are identified by name, structure, and abbreviation. and are abbreviations for benzene. and are abbreviations used for aromatics.
For amides and amines, , , and , alkyl, or aryl.
Classification of Alkyl Halides and Alcohols
Classification of Amines and Amides
Examples of Functional Groups in Medicine
|Functional Group||Primary (1°)||Secondary (2°)||Tertiary (3°)||Vinyl||Aryl||Phenyl|
|Alkyl halides (RX)|