Solid-Only Compounds

Solid only compounds are compounds that can only occur in the solid phase. These compounds are taken into account in the equilibrium calculations in a simplified manner, without the requirement to calculate fugacities for these compounds.

As these solids cannot appear in the vapor or in the liquid phase, the reference state of these compounds for enthalpy and entropy calculations in the solid phase, at reference temperature 298.15 K and reference pressure 101325 Pa. This choice of reference state makes that compounds for which no vapor or liquid data is available can still be configured.

Please mind that for consistent property values, the heat of formation, the absolute entropy and the Gibbs free energy of formation for these compounds in the PCD data files should therefore also be in the solid phase, at reference temperature 298.15 K and reference pressure 101325 Pa.

Typically, for solid-only compounds, the following compound data needs to be available:

• name
• chemical formula (optional)
• CAS registry number (optional)
• molecular weight
• solid phase heat capacity temperature correlation
• solid phase density temperature correlation
• heat of formation, absolute entropy (required when properties entropyF and enthalpyF are to be used)

Currently, the only solids supported in TEA are solid-only compounds. The solid-only compounds that come with TEA are available from solids.pcd.