Order-disorder transitions in low stage AsF6 graphites

Order-disorder transitions in low stage AsF6 graphites

Synthetic Metals, 2 (1980) 361 361 © Elsevier Sequoia S.A., Lausanne -- Printed in the Netherlands O R D E R - D I S O R D E R TRANSITIONS IN LOW S...

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Synthetic Metals, 2 (1980) 361

361

© Elsevier Sequoia S.A., Lausanne -- Printed in the Netherlands

O R D E R - D I S O R D E R TRANSITIONS IN LOW STAGE AsF 5 GRAPHITES

J. B. HASTINGS and C. R. FINCHER, Jr.

Physics Department, Brookhaven National Laboratory *, Upton, N Y 11973 (U.S.A.) M. MORAN and J. E. FISCHER

Moore School of Electrical Engineering and Laboratory for Research on the Structure of Matter, University of Pennsylvania**, Philadelphia, PA 19104 (U.S.A.)

Summary

X-ray scattering studies of low stage AsF5 graphites provide the first direct observations of the order-disorder transitions in these compounds. In CsAsF 5 the order parameter increases continuously to saturation over a broad range of temperature, in agreement with previous, indirect measurements. The low temperature structure in this compound does not appear to be the previously proposed 2a × 2a structure observed in the Stage 1 K and Cs compounds. Studies of the Stage 2 compound will also be presented and compared with the behavior for Stage 1.

*Work at Brookhaven National Laboratory supported by the Division of Basic Energy Sciences, U.S. Department of Energy, under contract DE-AC02-76CH00016. **Supported in part by NSF Division of Materials Science grant DMR 76-80994.