Central to the chemical equilibrium calculations in Chemics are thermodynamic properties of thousands of chemical species. These thermodynamic properties were collected from various legacy chemical equilibrium codes, including CEA, SDA03, SDA06, and ACE. While there are many chemical species common among these codes, there are some differences that can cause some difficulty. These are described below in the following table, along with a recommended resolution.
| Species | Database | Issue | Resolution |
| Bi | CEA | Bismuth is not found in any chemical species, making it impossible to solve an chemical equilibrium solution that includes bismuth as a reactant. | - Remove bismuth from reactants if in insignificant quantity - Use a different species database |
| H2O2 | SDA03 | Maximum temperature is 1500 K. Typically gives error of enthalpy or entropy not bounded. | - Don't use auto products - manually select all products except H2O2 - Use a different species database |