text: * when a non-innocent ligand is present, of hidden or unexpected redox properties that could otherwise be assigned to the central atom. An example is the nickel dithiolate complex, .
  * when the redox ambiguity of a central atom and ligand yields dichotomous oxidation states of close stability, thermally induced tautomerism may result, as exemplified by manganese catecholate, . Assignment of such oxidation states requires spectroscopic, magnetic or structural data.
  * when the bond order has to be ascertained along with an isolated tandem of a heteronuclear and a homonuclear bond. An example is thiosulfate  having two possible oxidation states (bond orders are in blue and formal charges in green):
  :The S–S distance measurement in thiosulfate is needed to reveal that this bond order is very close to 1, as in the formula on the left.