THERMAL-BEHAVIOR OF THE COPPER-SUBSTITUTED COBALT HYDROXIDE FLUORIDE SERIES CUXCO1-X(OH)F

The basic salt cobalt(II) hydroxide fluoride was obtained by partial h ydrolysis of a 0.2 M solution of CoF2. Mixed Co(II). Cu(II) hydroxide fluorides with an isomorphic substitution of Co(II) by Cu(II) ions up to 20% were also prepared. XRD data obtained on these compounds indica te that they are single-phase compounds, their X-tay powder patterns b eing almost identical to the Co(OH)(0.7)F-1.3 diagram, with Zn(OH)F-ty pe structure. However, their stoichiometries are very close to Co1-xCu x(OH)F (0 less than or equal to x less than or equal to 0.2). Thermal analysis studies carried out up to 1273 K in still air or under dynami c vacuum conditions show that in air CoO or a mixture of CoO and CuO i s formed as final product. In vacuum, at high temperature, with a Ta h eating surface, pure alpha-Co or a mixture of alpha-Co and Cu is forme d at about 973 K.