An Ellingham diagram is a graph showing the temperature dependence of the stabilityfor compound. The Ellingham diagram plots the Gibbs free energy change (ΔG) foreach oxidation reaction as a function of temperature. For oxidation of carbon, the redline is for the formation of CO: C(s) +
1
2
O2(g) ➔ CO(g)with an increase in the number of moles of gas, leading to apositive ΔS and a negative slope
