J. Phys. IV France 04 (1994) C9-109-C9-112
Parallel beam powder diffraction study on the AlC60 system (A=K, Rb)G. Faigel1, M. Tegze1, G. Bortel1, L. Forró2, G. Oszlányi2, 3 and P.W. Stephens4
1 Research Institute for Solid State Physics, P.O. Box 49, 1525 Budapest, Hungary
2 Laboratoire de Physique des Solides Semicrystallins, IGA, Departement de Physique, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
3 on leave from the Research Institute for Solid State Physics, P.O. Box 49, 1525 Budapest, Hungary
4 Department of Physics, State University of New York, Stony Brook, NY 11794-3800, U.S.A.
We report x-ray powder diffraction studies on RbxC60, and KxC60. It is shown that at room temperature there exist stoichiometric compounds in the RbxC60, and KxC60 systems at the x= 1 composition. Their equilibrium structures are pseudo body centered orthorhombic. The C60-C60 intermolecular separation (9.1 Å) is the shortest among the known alkali- fullerides. A first order phase transition is observed at about 380 K from the high temperature fcc phase to the room temperature orthorhombic phase.
© EDP Sciences 1994