X-ray diffraction in liquid ethyl alcohol

Abstract

X-ray diffraction patterns of liquid ethyl alcohol have been taken at temperatures of 25°C and -75°C with monochromatic Mo Kα radiation out to values of (sin θ)/λ = 1.2 and Fourier analyses of these curves carried out. The weighted radial atom distribution function shows a number of well-defined peaks. The first of these, at about 1.5A, corresponds to the C-C (1.54A) and C-O (1.43A) distances in the molecule, the two being superposed. This composite peak is completely resolved from the remainder. A peak at about 2.4A may be interpreted as due to the other C-O distance in the molecule. These are the only definite distances, corresponding to permanent neighbors, that would be expected. A most interesting feature is the existence of a peak at about 2.9A corresponding to intermolecular linkage of hydroxyl groups, similar to the situation found in liquid methyl alcohol. The area under this peak shows that each hydroxyl is linked to, roughly, two others, as was also found to be the case for methyl alcohol. Beyond this there are no very definite distances, the density curve rapidly approaching the average density.