XPS STUDIES OF GRAPHITE COMPOUNDS WITHOXYGEN, FLUORINE AND PENTAFLUORIDES

摘要

We have studied by the X-ray photoelectron spectroscopy graphite compounds with oxygen, fluorine,NbF5, MoF5, TaF5, SbF5 and, for comparison, the samples of fluorinated lignin. In F1s spectra of fluorinated graphiteoxides and fluorinated lignin was found a peak with the value of binding energies being intermediate between valuesin a typical ionic compound LiF and covalent compounds of type (CF)n and -(CF2-CF2)n-. The substances understudy, even at high oxidizer content at all synthesis stages contain structure fragments with carbon having sp2-hybridized orbitals of the valent electrons. The bond formed between fluorine and these fragments is of semi-ionictype at the used method of fluorination. The temperature which allows the semi-ionic fluorine-carbon bond formationin the investigated compounds is found to be below 100°C. The observation of semi-ionic state of fluorine in thefluorinated lignin allows to assume that the extended lamellar structure of initial substance is not necessary for theformation of semi-ionic bond between fluorine and carbon. In all penta-fluoride graphite intercalation compounds theF1s spectra consist of a single peak. In graphite intercalation compounds with NbF5 and TaF5 the C1s spectra consistof two peaks. In the Me3d spectra of all compounds investigated the peaks corresponding to MeF3 molecules was notobserved. Basing on the XPS data the model of electronic structure was proposed for compounds investigated.