The present work means to study the infrared spectra and to determinate energy spectra parameters of current carriers for graphite intercalation compounds of low stages with sulfur acid in the presence of different oxidizers, where oxidizers are K2Cr2O7, KMnO4, Ce(SO4)(2)4(NH4)(2)SO4. 2H(2)O, (NH4)(2)S2O8, and for low density graphite materials (flexible graphite foils) produced on their base.