REACTIONS IN THE SYSTEM GRAPHITE-CRO3-ACETIC ACID .1. REACTIVITY OF THE GRAPHITE

The conditions of reaction for the intercalation of graphite by chromium oxide from acetic acid solution have been put on a more general basis. Intercalation is possible at all temperatures between 20 and 120 °C. The reaction temperature determines the stage number of the compound formed, for which values have been found between 8 and 2. At temperatures above 70 °C, and inhibition of the reaction has been found, caused by decomposition of the intercalate between the graphitic layers. This irreversible effect is observed most clearly in flakes larger than 100 μm in diameter. Another, reversible inhibition of the reaction has been found which intensifies towards lower temperatures and smaller particles. This effect prevents the intercalation ofpowder graphite at 25 °C. Probably a protective layer of adsorbed molecules is formed around the crystals. These inhibition effects are described quantitatively by the degree of penetration" which is obtained from X-ray measurements. © 1979."