Nouvelles données sur les composés graphite VOF 3

Abstract

A new method of synthesizing graphite-VOF 3 is presented. The action of VOF 3-saturated anhydrous hydrogen fluoride on HOPG gives, after several weeks, a compound C 40 VOF 3. A radiocrystallographic analysis was carried out. The 001 reflexions shown on Fig. 1 allow determining the identity period I c = 18.07 A ̊ . This value is confirmed by the macroscopic dilation of the samples. If the positions of atoms in the intercalated molecules is the same as that shown in Fig. 2, the structure factor can be calculated and the values obtained are in good agreement with the experimental values. The hk0 reflexions indicated on Fig. 3 show the 100 and 110 graphite reflexions as well as others: the narrowness of these latter ones proves the existence of a certain organization of the intercalant between the carbon layers. A study using the double rotation technique of some hk0 reflexions is represented on Fig. 4; it allows indexing in a hexagonal cell of parameter a = 15.53 A ̊ and for which the a axis makes an angle of 30° with that of the graphite. Furthermore a study of intensities of graphitic hk 1 reflexions confirmed that the c axis parameter is equal to the identity period given above. The rotating crystal photograph of Fig. 5 shows that VOF 3 molecules are organized without correlation between layers.