[en] Among a wide variety of solid state materials, alkali lanthanide double phosphates are the subject of extensive spectroscopic investigations for their application as laser active materials. The edge of absorption in this compound is at rather high energies, which makes them suitable as efficient host for luminescent materials. Spectroscopic properties of Sm³⁺-doped K₃Y(PO₄)₂ are reported basing on the high resolution absorption and emission spectra for various temperatures mainly at 4, 10, and 293 K from UV to IR range. The effects of concentration and temperature on intensities and shape of the observed bands were studied. Radiative transition probabilities were calculated from absorption spectra and Judd–Ofelt parameters evaluated. The excited state dynamics will be discussed based on the decay time measurement. - Highlights: • Sm³⁺: K₃Y(PO₄)₂ crystals were synthesized via a solid-state reaction. • The spectroscopic properties of the samples were investigated at 293 and 11 K. • Concentration quenching mechanisms and possible relaxation channels were discussed. • The Judd–Ofelt intensity parameters are calculated. • Sm³⁺: K₃Y(PO₄)₂ is a promising material for 405 nm pumped phosphor.

[en] Highlights: • Three selected inorganic hydrated salts in water and methanol solutions were acoustically and spectroscopically investigated. • All investigated electrolytes are strong in aqueous solutions but weak in methanol. • Substantial differences of the coordination abilities of the cations are manifested, especially in acoustic properties. - Abstract: Hydrated salts, MgCl_2·6H_2O, CuCl_2·2H_2O and EuCl_3·6H_2O when dissolved in methanol, conserve their original coordination numbers, probably dissociating two chloride anions (magnesium chloride), stepwise in equilibrium reactions (copper chloride) or probably only one Cl"− (europium chloride). Water hydrating molecules are almost fully removed from the coordination shell only in the case of MgCl_2·6H_2O. The above conclusions were drawn from analyzing the acoustic and densimetric properties of the title systems and confirmed by conductivity tests. The results are also compared to those in aqueous solutions. The emission and excitation spectra obtained for europium chloride were applied as spectroscopic probes of solution structure, as well as of the number of existing species and their symmetries.