A hydrocarbon is an organical chemical compound consisting only of carbon and hydrogen.
They all consist of carbon backbone and atoms of hydrogen attached to that backbone.
There are basically three types of hydrocarbons: saturated hydrocarbons,
which don't have double, triple or aromatic bonds, unsaturated hydrocarbons,
which have one or more double or triple bonds between carbon atoms, and aromatic hydrocarbons,
which have at least one aromatic ring in addition to whatever bonds they have.
Unsaturated hydrocarbons are divided to:
Geologically-extracted hydrocarbons are referred to as petroleum (literally "rock oil") and are a significant source of fuel and raw material as a feedstock for the production of organic chemicals.