Molecular
formula (chemical formula): A list of all the elements,
plus how many atoms of each element, are present in a
chemical compound. The number of atoms is
indicated with a subscript after the element's symbol, except when
only one atom of an element is present; in this case no subscript
is used. For example
methane
has a
molecular
formula of CH
4, indicating it contains one carbon atom
and four hydrogen atoms.
The
Hill system is generally used for
organic
compounds.
In this system, the correct
molecular
formula format is: carbon, hydrogen, then all other elements in
alphabetical order.
When a
molecule
has bonding other than
covalent,
groups of atoms such as complex
anions
or
waters
of
hydration
are usually listed together.
