Synthesis and Spectroscopic Study of Europium(III) in Heteropolyanion [EuP$\text{}_{5}$W$\text{}_{30}$O$\text{}_{110}$]$\text{}^{12-}$

The heteropolyanions of Preyssler anion [NaP$\text{}_{5}$W$\text{}_{30}$O$\text{}_{110}$]$\text{}^{14-}$ and its europium-encrypted derivative [EuP$\text{}_{5}$W$\text{}_{30}$O$\text{}_{110}$]$\text{}^{12-}$ were prepared and spectroscopically characterized. The compositions of these heteropolyanions were verified based on the results from elemental and thermogravimetric analysis and the data of spectrophotometric determination of tungsten contents. Absorption in the UV-vis and IR region and luminescence spectra, as well as results of the laser-induced europium ion luminescence spectroscopy, obtained for solid complexes and their solutions, were analysed. Both in solid and solution the europium-encrypted derivative has three water molecules of hydration.