Identification of the intercalant species in SbCl5-graphite using Mössbauer spectroscopy

¹²¹Sb Mössbauer spectra of SbCl₅-graphite have been obtained. The spectra provide clear evidence for the presence of the acceptor molecular ion SbCl₆^-(Sb⁵⁺ and neutral SbCl₃(Sb³⁺ in the intercalate layers, with weak evidence for neutral intercalated SbCl₅. Lineshape analyses of the Sb³⁺ region of the spectra further indicate that two chemical Sb³⁺ sites fit the data significantly better than one site. We attribute the second Sb³⁺ site to SbCl₄^- and find the concentration ratio SbCl₄^-]/SbCl₃] 0.25. Samples prepared by the reaction of graphite with vapor mixtures of SbCl₅ and SbCl₃ were found to exhibit dramatically higher concentrations of SbCl₃ than those samples prepared from a reaction with SbCl₅ alone. This latter result is interesting in view of the fact that the reaction of graphite with SbCl₃ vapor does not lead to an intercalation compound.