When several atoms are covalently bonded into an ion such as the ion goes through many chemical reactions as a unit, behaving like a single-atom ion of the same charge. Carbonate ions can form salts with or other positive ions just as fluoride ions can.

is lithium carbonate and, like , the crystal structure of this salt has two +1 ions () for every -2 ion . , with one positive and one positive H+ ion, is known as lithium hydrogen carbonate (or in an older nomenclature, lithium bicarbonate since it contains twice as much carbonate per lithium atom as does).

Many negative ions, or anions, are built from several covalently bonded atoms; the carbonate ion is an example. Positive ions, or cations, with several atoms are less common, in comparison with single-atom metal ions such as or .

One exception that we have seen already is the ammonium ion, , in which four H atoms are covalently bonded around a central nitrogen.

Carbonic acid would be intrinsically stronger than boric acid because of the greater electronegativity of carbon over boron, but delocalization adds an extra bit of acid strength. There is no delocalization in the borate ion, , since every electron is either tied up in a specific electron-pair bond between atoms or occupied as an oxygen lone pair.

Even with extra help from delocalization, carbonic acid is weak enough to be drunk in carbonated beverages. Delocalization really becomes important in increasing acidity in the next molecule to be discussed, nitric acid.