The chemical formula Fe(NO2)2 represents the compound iron(II) nitrite. The formula denotes the number of atoms of each element that are contained in a single molecule. Iron(II) nitrite consists of one atom of iron, two atoms of nitrogen and four atoms of oxygen.
Iron(II) nitrite, which may also be referred to as ferrous nitrite, is made up of the ions iron(II) and nitrite. As indicated by the Roman numerals, the iron ion carries a charge of plus 2. The nitrite ion carries a charge of minus 1. When the two ions combine to form a single compound, two ions of nitrite are needed to balance the charge of one ion of iron(II).