CFC (chlorofluorocarbons) seem to be associated with the ozone depleti
on. Attempts have been tackled to turn towards substitutes which do no
longer contain chlorine atoms. The corresponding processes need perfo
rming fluoration catalysts working in severe conditions. These catalys
ts, based on trivalent chromium oxide and fluoride, are either bulky o
r supported mainly on alumina or carbon. They are amorphous at the X-r
ay diffraction scale from impregnation to activation. X-ray Absorption
Spectroscopy (XAFS, X-ray Absorption Fine Structure), using synchrotr
on radiation, gives information about short-range order and is thus we
ll-adapted for non crystalline materials. We describe here the case of
Cr(6% in weight)/C. After impregnation of an aqueous solution of CrO3
on carbon, and drying under N-2 the initial Cr(VI) phase is nearly to
tally reduced into Cr(III). The activation process by HF occurs very s
oon, the catalyst tends towards an amorphous CrF3, altough it still re
mains oxygen. The nature of this oxygen will be discussed.