The ultraviolet absorption spectrum of a crystal of Cs2NaTbCl6 has been recorded at 15 and 35 K. Spectral features have been assigned to magnetic dipole zero phonon lines and TbCl63- moiety mode vibronic structure. A comparison is made of the derived electronic energy level scheme with that from two-photon excitation experiments and the agreement is good. The differences in spectral selection rules for these two approaches are highlighted. (C) 2011 Elsevier B. V. All rights reserved.