Pressure-induced structural phase transition in the Bechgaard-Fabre salts

The crystal structures of the quasi-one-dimensional organic salts (TMTTF)2PF6 and (TMTSF)2PF6 were studied by pressure-dependent X-ray diffraction up to 10 GPa at room temperature. The unit-cell parameters exhibit a clear anomaly due to a structural phase transition at 8.5 and 5.5 GPa for (TMTTF)2PF6 and (TMTSF)2PF6, respectively.