Structure of second-stage graphite–rubidium, C24Rb
Abstract
The X-ray diffraction patterns from second-stage rubidium–graphite, C24Rb, have been measured at high resolution in the basal plane for samples made from oriented, exfoliated graphite. The pattern at 5 K has been indexed on the basis of both a simple static distortion wave and a √43 ×√43 superlattice consisting of nearly commensurate √7 ×√7 patches of alkalimetal ions bounded by domain walls. This model has been tested by least-squares refinement of all the observed intensities and peak positions and compared with the static distortion wave predictions. The C24Rb system, because of the small domain size, turns out to be particularly suitable for comparing these approaches, which are seen here to be equivalent.