Composition and temperature dependence of the Raman spectra of the molten LnU-CsI (Ln= Ce, Dy, Ho) mixtures have been measured. The changes of the vibrational modes upon melting the polycrystalline compounds CS3L11I6 and Cs3Dy2l9 have also been measured. The spectral data suggest that, as for other LnX3-AX (Ln: lanthanide, A: alkali, X: F, Cl, Br) binaries, the six-fold coordination around the lanthanide is preserved at all compositions, including pure LnH melts, where a loose network-like

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... ture is formed. The electronic absorption spectra of vapors over solid H0I3 and molten H0I3-CSI, 50:50 mol% mixtures have been recorded at different temperatures. Using the literature vapor pressure data for Hol3(s), the molar absorptivity and the oscillator strength o f the Ho3+ 4f<-4f (5G6<-5Ig) hypersensitive transition have been calculated. The obtained values are compatible with the low symmetry semi-trigonal structure for the Hol3(g) species. The spectra of vapors in equilibrium with the 1:1 binary liquid mixture show the presence of two bands, which are assigned to the 5G6<-5Ig transition of two different hohmum species. One is associated with the Hol3(g) and the other with a caesium-holmium iodide vapor complex with an anticipated CsHoL stoichiometry.