For selecting the most suitable ammoniate as a heat storage material we have reviewed all the available literature since 1860. This data reveal that we can order the dissociation temperature and the enthalpy of reaction of different ammoniates. We show that all data can be represented by a single master curve. This curve shows that ammoniates belonging to the alkali metal periodic group have the lowest energy pro ammonia molecule, whereas transition metals (3d) have the highest energy pro ammonia molecule. These trends can be used to select the most suitable ammoniates under certain working conditions.