The absorption and luminescence spectra and the luminescence lifetime of the excited state 2F5/2 of Yb3+ ions in CCl4 – GaCl3 – Yb3+ solutions have been measured. Information was obtained on the Stark splitting of levels, on the absorption and stimulated emission cross sections, and on the quantum yield of Yb3+ luminescence. The spectral dependences of the gain cross section are calculated for different relative inverse populations of the 2F5/2 excited state. Based on an analysis of the spectral and laser properties of Yb3+, it was concluded that the use of CCl4 – GaCl3 – Yb3+ solutions as the active medium of a liquid ytterbium laser is promising. Keywords: carbon tetrachloride, ytterbium, absorption, luminescence, lifetimes, Stark splitting, gain cross section