Carbon capture and storage (CCS) technologies result in demands on thermodynamic-property models that were previously unknown in energy technologies. This article summarises recent developments allowing for an accurate description of thermodynamic properties of mixtures that are typical for oxyfuel processes and for compression and transport of separated CO ₂. It addresses homogeneous fluid state as well as phase equilibria of fluid and solid phases. However, phase equilibria with scrubbing agents, as they are common for post combustion processes, are out of the scope of this article.