We have obtained IR absorption spectra of a C₂F₆ gas and a C₂F₆ cryosolution in Xe (T = 163 K) in the fundamental and overtone ranges. We have interpreted 28 bands of ¹²C¹²CF₆ and three bands of ¹³C ¹²CF₆. In the spectral ranges that correspond to vibrations that are combinations with ?₁, ?₇, and ? ₅, we observe multiplets, which we attribute to interactions of the type of Fermi resonances between the states ?₁(A_1g) ∼ ?₆(A1g), ?₇(E_g) ∼ ?₆ + ? ₁₁(E_g) ∼ 2?₈(E_g), ? ₅(A_2u) ∼ ?₈ + ?₁₁(A _2u). We reveal an anomalous intensity distribution in the spectrum of an asymmetric isotopologue. For the basic and isotopic configurations of per- fluoroethane, we calculate the coefficients of shapes of vibrations and the intensities of absorption bands. We reveal that the behavior of the groups ¹²CF₃ and ¹³CF₃ is indifferent to the excitation of doubly degenerate stretching vibrations ?₇(E _g) and ?₁₀(E_u).