COSMO-RS (short for COnductor like Screening MOdel for Real Solvents) is a quantum chemistry based equilibrium thermodynamics method with the purpose of predicting chemical potentials µ in liquids.It processes the screening charge density σ on the surface of molecules to calculate the chemical potential µ of each species in solution. As an initial step a quantum chemical COSMO calculation for all molecules is performed and the results (e.g. the screening charge density) are stored in a database. In a separate step COSMO-RS uses the stored COSMO results to calculate the chemical potential of the molecules in a liquid solvent or mixture. The resulting chemical potentials are the basis for other thermodynamic equilibrium properties such as activity coefficients, solubility, partition coeffici