X-Ray Diffraction Study of Liquid 1, 1, 1-Trichloroethane by the Energy-dispersive Method

Abstract

The X-ray scattering intensities from liquid 1, 1, 1-trichloroethane (TCE) were measured at room temperature by the energy-dispersive method. Based on the local lattice structure model, structure simulation studies for TCE were carried out. A bcc model with random orientation of the methyl groups has well-reproduced the experimental data.
The number of molecules in the structure region, n, was determined by a trial and error method, and a least-squares refinement was carried out to determine the following four parameters; the lattice constant of the bcc cell a, the Prins parameter D, the radius up to the continuous region R_c and its damping factor I_c. The refined parameters with the standard deviations in parentheses are: a=6.78(0.11)Å, D=0.049(0.009)Å, Rc=12.70(0.48)A, and l_c=3.1(1.5)Å with n=51. These results indicate that TCE molecules are arranged in the head-tail head-tail packing (Fig.1) with the first nearest-neighbor distance of 5.87(0.09)Å in the liquid.