For its nomenclature we use
Stoichiometric nomenclature: it is formed by two words. The first word is
the name of the nonmetal with a Greek prefix that shows us the number of atoms
of nonmetal, the second word is the name "oxide" with a Greek prefix that shows
us the number of atoms of oxygen.
The Greek prefixes are:
The prefix mono- is used
only before "oxide" and when the ratio is 1:1.
The IUPAC also accepts Stock´s nomenclature for these oxides, though it is
better to use the stoichiometric nomenclature when all the atoms are nonmetals
and Stock´s nomenclature when there are metal and non metal atoms.