In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom assuming all of its bonds to other atoms are fully ionic. It describes the degree of oxidation of an atom in a chemical compound. Conceptually, the oxidation state may be positive, negative or zero. Oxidation state is useful for estimating the distribution of electric charge within molecules, especially for those containing primarily ionic bonds, and less so for those with primarily covalent bonds.