Interlayer structural models of Beulah Zap lignite based on its wide angle X-ray scattering
Wide-angle X-ray scattering (WAXRS) in the 0.5-2.5 Angstrom(-1) region of the intensity curve of Beulah Zap (BZ) lignite indicates that the average distance between adjacent layers is ca. 3.5 Angstrom. The resulting interlayer structural curve, calculated by Fourier transform from the WAXRS intensity, indicates that only two layers occur in the average short-range structural domain of BZ with the distances between atoms in the adjacent layers occurring between 3.4 and 5.7 Angstrom. Both the WAXRS intensity curve (in reciprocal space) and the interlayer structure curve (in molecular space) are consistent with an average short-range structural domain in which the flexible spacers (attachments) between the polycyclic units are important contributors and where the PC units in the adjacent chains are not eclipsed.