Organic chemistry

Carbon compounds, functional groups, reaction mechanisms, and chirality

What is organic chemistry?

Organic chemistry is the study of carbon-containing compounds — an enormous branch of chemistry, since carbon is unusually good at bonding with itself and many other elements, forming everything from the simplest fuel molecules to the complex molecules that make up living things.

Why carbon is special

A carbon atom can form four strong bonds, and it can link up with other carbon atoms to form long chains, branching structures, and rings. No other element does this as readily or as stably. This is why such an enormous variety of organic molecules exist — millions of known compounds — from small molecules like methane (natural gas) to huge molecules like DNA.

Hydrocarbons: the simplest organic molecules

The simplest organic compounds, called hydrocarbons, contain only carbon and hydrogen. Methane, propane, and octane (a major component of gasoline) are all hydrocarbons, differing mainly in how many carbon atoms are chained together. These are the basic fuels that power much of the modern world.

Functional groups

Beyond plain hydrocarbons, organic molecules often contain functional groups — specific small groupings of atoms attached to the carbon backbone that give the molecule characteristic chemical behavior. For example, an -OH group makes a molecule an alcohol, and a -COOH group makes it an acid. Recognizing functional groups lets chemists predict how a molecule will react, even in a molecule they've never seen before.

Why organic chemistry matters

Organic chemistry underlies plastics, fuels, medicines, dyes, and the chemistry of life itself — proteins, fats, sugars, and DNA are all organic molecules. Understanding how to build, modify, and break down organic molecules has made possible everything from life-saving drugs to the synthetic materials used in everyday products.