Electronic spectral studies of some lanthanoid (III) [Ln(III)] ions, namely Pr(III), Nd(III), Sm(III), Eu(III) and Er(III), doped in two pseudo-garnet environments, sodium molybdate and sodium m-silicate, have been studied for the determination of their oscillator strength (f(JO)) values. The intensities of the fluoresence emissions for Eu3+ in different media have also been recorded. The positions of spectral bands in the electronic spectra as well as the oscillator strength values for some prominent (preferably) hypersensitive transitions have been studied as a function of ground state J values. (C) 1997 Elsevier Science B.V.