A molecular dynamics study of the adsorption of CO2 on NaCl (100) is presented. The model potential includes short-range Buckingham atom-atom and charge-charge terms for the molecule-molecule interaction and Lennard-Jones atom-atom and charge-charge terms for the molecule substrate interactions. Calculations have been performed for finite patches and for samples with periodic boundary conditions. The adlayer can form domains with the 2x1 herringbone arrangement. The structure of the adlayer as a function of temperature is discussed in terms of various distribution functions. The vibrational properties of the adlayer (internal and external vibrations) are calculated and compared with available experimental data.