Funds from this grant provide two years of continuing administrative and research support to the Extreme Physics and Chemistry Community of the Deep Carbon Observatory (DCO). One of four scientific communities within the DCO, the Extreme Physics and Chemistry Community concerns itself with crystals, fluids, and magmas at the high pressures and temperatures characteristic of deep Earth. Supported research will extend measurements on carbon-bearing systems to previously inaccessible conditions, combining an extraordinary array of experimental techniques with careful computational studies on challenging chemical systems. Under the direction of UCLA geophysicist Craig Manning, as many as 19 distinct research projects are envisioned during the next two years, with a focus on simultaneously conducting numerical simulations and laboratory measurements on the same physical properties of the same materials. Also supported under this grant is the compilation and publication of a comprehensive open-access database of thermochemical properties of carbon-bearing minerals, melts, and fluids, as well as their mixtures, to lower-mantle pressure and temperature conditions. The continued research of the Extreme Physics and Chemistry Community promises to contribute in powerful ways to the DCO’s goal of radically advancing our understanding of deep Earth carbon.