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:
| 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 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.