This is the subset of the Interface Force Field (IFF) implemented in CHARMM-GUI as of 2023-2-23. It contains parameters for gas molecules, FCC metals, metal oxides, metal hydroxides, battery oxides, clay minerals, mica, calcium sulfates, cement minerals, tobermorite, silica, hydroxyapatite, transition-metal dichalcogenides, and graphitic materials. IFF atom type labels are proprietary to the CHARMM-GUI implementation, equal to IFF force field types starting with an added letter “I”. This implementation of IFF covers only parameters in CHARMM using a 12-6 LJ potential. It excludes a separate set of IFF parameters compatible with CFF, PCFF, and COMPASS using a 9-6 LJ potential, as well as customized parameters for OPLS-AA and AMBER for selected compounds. This implementation also excludes IFF parameters for polymers (PEG, PMMA), and several solvents. The parameters archived in this OpenKIM model for Molybdenum Disulfide are tuned for a more accurate equilibrium crystal structure, and differ slightly from those in CHARMM-GUI which are tuned for more accurate infrared spectra. See complete documentation and updates on the website (https://bionanostructures.com/interface-md/).