A Frost diagram or Frost–Ebsworth diagram is a type of graph used by inorganic chemists in electrochemistry to illustrate the relative stability of a number of different oxidation states of a particular substance. The graph illustrates the free energy vs oxidation state of a chemical species. This effect is dependent on pH, so this parameter also must be included. The free energy is determined by the oxidation–reduction half-reactions. The Frost diagram allows easier comprehension of these reduction potentials than the earlier-designed Latimer diagram, because the “lack of additivity of potentials” was confusing. The free energy ΔG° is related to the reduction potential E shown in the graph by the formula:  or , where n is the number of transferred electrons, and F is the Faraday constant  ). The Frost diagram is named after , who originally invented it as a way to "show both free energy and oxidation potential data conveniently" in a 1951 paper.