On the structure of simple molecular liquids SbCl5 and WCl6

Neutron diffraction measurements on liquid antimony pentachloride and tungsten hexachloride have been carried out using the Studsvik liquids and amorphous diffractometer (SLAD) at the Studsvik Neutron Research Laboratory. The corrected structure factors have been interpreted by means of reverse Monte Carlo modeling which provides large structural models, containing thousands of atoms, that are consistent with the experimental data within their uncertainties. From these models, partial structure factors and pair correlation functions can be calculated. It is demonstrated that the intramolecular structure can be determined on the basis of data extending up to 10 Angstrom (-1). SbCl(5) is found to have a trigonal bipyramidal shape in the liquid, while liquid WCl(6) consists of octahedral molecules. The intermolecular structure of liquid SbCl(5) and WCl(6) seems to be determined largely by steric effects (excluded volume and molecular shape).