Ellingham Diagram
Explore oxide, carbide, nitride, fluoride and chloride formation. Choose one reaction family at a time, inspect phase changes, and compare carbon or hydrogen with oxides under the stated standard conditions.
Oxide stability and reducing agents
ΔG° per mole of O₂ consumed. Lower formation lines indicate a stronger affinity for oxygen.
Each curve is drawn only within its source range. FeO below 570 °C is a metastable reference, not an equilibrium stability field.
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Read the numbers
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| Formation reaction | Category / basis | ΔG° kJ/mol O₂ | Reference phases / limits |
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Equations and how to interpret a crossing
ΔG° = ΔH° − TΔS°
ΔG°reduction = ΔG°reductant oxidation − ΔG°oxide formation
Both formation reactions are normalized to one mole of O₂. A negative difference favors oxygen transfer to the selected reducing agent in the stated standard states. It does not measure the energy bill of a furnace or establish its reaction rate.
Compare only reactions on the same molar basis. A crossing describes equality of the plotted standard-state formation energies; actual gas pressures and phase activities determine equilibrium.
System boundary and data limitations
Use the Baur–Glässner model to examine the gas ratio required to reduce iron oxides. Neither diagram includes reaction kinetics, heat transfer, gangue, slag, or equipment performance.
Sources and reproducibility
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CSV exports include the active family, normalization basis, visible curves and their validity. The oxide family also includes the probe reduction comparison. SVG exports contain the current diagram and its legend.