The article analyses the existing set of data on the temperature dependences of the main kinetic coefficients and the IR-reflection spectra R(ν) of the PbSb 2 Te 4 crystals. The form of the Fermi surface is discussed. The anisotropy of holes' effective mass and relaxation time is estimated. The complex structure of the valence zone is confirmed, the values of these parameters are refined. Complex X-ray studies of the structure and composition of PbSb 2 Te 4 samples gave the possibilities to clarify the real crystal structure and explain the number of features in the IR-reflection spectra.