BiCl3-graphite: an environmentally stable low-dimensional compound Original Research Article

Bismuth(III) chloride has been intercalated from the gas phase into highly oriented pyrolytic graphite. The as-prepared intercalation compound was investigated by X-ray diffraction and by selected area electron diffraction. The product was a mixture of second and third stages, with an in-plane lattice showing the typical rectangular structure of BiCl3-graphite. The sample was exposed to boiling water for 15 weeks and the stages as well as the in-plane lattice were investigated at different periods of time. In the first 4 weeks, no stage conversion could be detected, with the in-plane lattice showing the original diffraction pattern with very well resolved diffraction spots. X-ray diffraction measurements gave evidence of increasing stage disorder by exposure to the boiling water. A stage conversion from a second to a fifth stage was detected between the 4th and the 6th week. A partial deintercalation with appearance of the graphite (002) reflection was also observed. Between 6 and 15 weeks in boiling water, the sample showed different in-plane lattices dependent on the region of the sample examined. Some areas showed the original rectangular pattern, a few other areas a Moiré pattern, both types giving very well resolved diffraction spots. The Moiré pattern indicates increasing domain twinning. Other regions in the sample were totally emptied of intercalated materials, and a few other regions showed a diffraction pattern with more or less well developed diffraction rings. These results gave evidence for the beginning decomposition of the intercalation compound.