Synthesis, characterization, and properties of reduced europium molybdates and tungstates

Single crystals of K0.094Eu0.906MoO4, K0.097Eu0.903WO4, EuWO4, and EuMoO4 were grown from molten chloride fluxes contained in vacuum-sealed fused silica and structurally characterized via single crystal X-ray diffraction. The in situ reduction of Eu3+ to Eu2+ was carried out using Mo, W, and Zn as metal reducing agents. All four compounds crystallize in the tetragonal space group of I41/a and adopt the scheelite (CaWO4) structure type. The magnetic susceptibility of the reported compounds shows paramagnetic behavior down to 2K. 151Eu Mössbauer spectroscopy was used to analyze the relative Eu2+ and Eu3+ content of the samples. All the compounds were further characterized by EPR, and UV-vis spectroscopy.