Interlayer structural models of Beulah Zap lignite based on its wide angleX-ray scattering

Wide-angle X-ray scattering (WAXRS) in the 0.5-2.5 Angstrom(-1) region of t he intensity curve of Beulah Zap (BZ) lignite indicates that the average di stance between adjacent layers is ca. 3.5 Angstrom. The resulting interlaye r structural curve, calculated by Fourier transform from the WAXRS intensit y, indicates that only two layers occur in the average short-range structur al domain of BZ with the distances between atoms in the adjacent layers occ urring between 3.4 and 5.7 Angstrom. Both the WAXRS intensity curve (in rec iprocal space) and the interlayer structure curve (in molecular space) are consistent with an average short-range structural domain in which the flexi ble spacers (attachments) between the polycyclic units are important contri butors and where the PC units in the adjacent chains are not eclipsed.