Accurate representations of the thermochemistry and phase equilibria of relevant molten salt constituents and their aggregate behavior are critical to the development, design, operation, and licensing of any molten salt reactor (MSR). This need is currently being addressed by the creation of a dedicated, high quality/validated MSR thermochemical database, the Molten Salt Thermal Properties Database-Thermochemical (MSTDB-TC). MSTDB-TC is being populated with prioritized models and values for vapor species, and liquid and crystalline phases of chloride and fluoride fuel and coolant salts with relevant fission product and transuranic elements, and more recently with corrosion-relevant systems with chromium, iron, and nickel. Multi-cation crystalline and melt solution models are being incorporated, including newly developed relations as necessary, to obtain real system behavior.