Hydrocarbons Fossil Fuels Hydrocarbons compounds  Elmhurst College
Alkanes or Chime Alkynes or Chime  Rings or Chime  Chemistry Department
Alkenes or Chime Aromatic or Chime Boiling Points  Virtual ChemBook

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CLASSIFICATION OF HYDROCARBONS

 
The term HYDROCARBONS means organic compounds which contain only carbon and hydrogen. By using this definition, four classes of hydrocarbons are included: alkanes, alkenes, alkynes and aromatic.

The simplest compounds containing 2 carbons shown on the LEFT are as follows:

 Alkanes

Alkenes

Alkynes
 SATURATED means that each carbon is bonded to four other atoms through single covalent bonds. Hydrogen atoms usually occupy all available bonding positions after the carbons have bonded to each other.  UNSATURATED hydrocarbons contain either double or triple bonds. Since the compound is unsaturated with respect to hydrogen atoms, the extra electrons are shared between 2 carbon atoms forming double or triple bonds.
 PARAFFINS which is derived from a Latin word meaning "little activity", and means that the compounds are very unreactive.  Alkenes are also called OLEFINS because they form oily liquids on reaction with chlorine gas.  Alkynes are also generally known as ACETYLENES from the first compound in the series.

AROMATIC COMPOUNDS

Aromatic compounds derive their names from the fact that many of these compounds in the early days of discovery were grouped because they were oils with fragrant odors, hence the name aromatic.

The current definition of aromatic compounds includes only those with a benzene ring, which is a special six carbon ring compound with three alternating double bonds. This structure imparts unique properties to benzene which are different from other ring compounds.