Experimental densities for the CO2 (1) + thiophene (2) binary mixtures are reported from 313 to 363 K and up to 25 MPa. Densities were measured for thiophene and for binary mixtures at five different compositions, x(1) = 0. 1990, 0.3818, 0.5661, 0.6996, and 0.9217. Densities of thiophene were correlated by four different models, the Benedict-Webb-Rubin-Starling equation of state (BWRS EoS), the Tait equation (TE), the Toscani and Szwarc (TS) model, and a proposed modification for this last model (MTS). These models represent densities of thiophene with a percent standard deviation of 3.90 x 10(-3), 1.97 x 10(-2), 2.76 x 10(-2), and 5.54 x 10(-3), respectively. The excess molar volumes were determined using densities for thiophene calculated from the BWRS EoS and densities for CO, calculated from the Span-Wagner EoS. The volumetric behavior and excess molar volumes of CO2 + thiophene mixtures were modeled using the PC-SAFT EoS. (c) 2005 Elsevier B.V. All rights reserved.