The above equations are stated for an arbitrary-order polynomial, but the Gas-phase Kinetics package is designed by default to work with thermodynamic data in the form used in the NASA chemical equilibrium code. [6] In this case, seven coefficients are needed for each of two temperature ranges. These fits take the following form, where the temperatures are in Kelvin:
 | (2–29) |
 | (2–30) |
 | (2–31) |
Note: The Gas-phase and Surface Kinetics Pre-processors allow for additional temperature ranges. Details of the thermodynamic data format options are included in Thermodynamic Data of the Chemkin Input Manual Input Manual.