Naming Ionic Compounds Containing Oxyanions

• Many polyatomic ions are oxyanions, anions containing oxygen.
• When a series of oxyanions contain different numbers of oxygen atoms, they are named systematically according to the number of oxygen atoms in the ion.
• If there are two ions in the series, the one with more oxygen atoms is given the ending -ate and the one with fewer is given the ending -ite.

NO3− nitrate SO42− sulfate NO2− nitrite SO32− sulfite