I need to do thermodynamic calculations, but do not know where to find reliable data for sub-stoichiometric tantalum carbide. Your help is greatly appreciated.
I would start with: A theoretical study of the potential energy curves and spectroscopic constants of TaC and TaC(+) by Balasubramanian, K in ChemPhysLett, 1998, it cites numerous earlier works, and there are several other papers in the series. You may have to work out the thermodynamics from the computed parameters but that is not too difficult for small systems.