| ° | standard state property |
| G | Gibbs free energy |
| H | enthalpy |
| ΔfH° | enthalpy of formation from the elements |
| K | equilibrium constant |
| Kred | equilibrium constant reduced to standard conditions |
| P | pressure [MPa] |
| R | gas constant (8.31441 J/K) |
| S | entropy |
| S° | third law entropy at standard conditions |
| T | temperature [K] |
| V | volume |
| a | activity |
| cp | heat capacity |
| ni | number of moles of component i |
| f | fugacity |
| x | mol fraction |
| α | coefficient of thermal expansion |
| β | coefficient of compressibility |
| Δ | change of a property for a reaction |
| µ | chemical potential |
| ν | stoichiometric coefficient |
| AR | vector of ln Kred values |
| B | matrix of the stoichiometric coefficients |
| D° | vector of third law entropies and enthalpies of formation |
| E | identity matrix |
| W | matrix holding the weighting factors |
| F | objective function |