A STUDY OF THE REACTIONS OF FLUORINE WITH CHROMIUM AND IRON AT HIGH-TEMPERATURES BY MATRIX-ISOLATION IR SPECTROSCOPY

Apparatus suitable for characterising the molecular species produced w hen fluorine reacts with a high-temperature metal surface is described and its use illustrated by identifying the species formed when fluori ne is passed over heated chromium or iron within a temperature range u p to 1000 degrees C. The species so formed are isolated in argon matri ces and characterised by infrared spectroscopy. Metal isotope frequenc y shifts were used to support identification and the molecular species thus identified included CrF4, CrF3, CrF2, FeF3 and FeF2. For each of the systems studied, it was found that the distribution of reaction p roducts was markedly dependent on temperature. The technique could be generally applicable to the study of any high-temperature metal-fluori ne system.