Synthesis and characterization of SrTeO₃using reducted telurium into a rongalite solution

In this work a new methodology to synthesize strontium tellurite on the base of reduction of tellurium is presented. The Tellurium comes from oxidation stage 0 to -2, afterward it is mixed with a strontium salt, strontium chloride, in aqueous solution. In this process a fast chemical reaction of substitution it is realized. In order to make the optical characterization, the absorption in the UV-visible range was measured leading to compute direct and indirect band gap energies. The obtained strontium tellurite was a black powder after to be rinsed several times with deionized water, the obtained Band gaps values were 2.85 and 1.75 eV for direct and indirect respectively. From the Raman spectrum were identified three related peaks: at 118 cm-1 corresponding to SrO, 697 cm^-1corresponding to (TeO₃)^2-(v₃). and 776 cm^-1corresponding to (TeO₃)^2-(v₁). The infrared response shows SrO at 526 cm^-1, strontium oxide at 617 cm-1 plus O-H vibration and bending vibration H-O-H. Finally from transmission electron microscopy two crystallographic phases were detected, the monoclinic and the triclinic structures.