Structural, dielectric and vibrational studies of the new mixed solid solution of thallium potassium sulfate selenate tellurate

The new mixed compound Tl1.89K0.11(SO4)(0.9)(-SeO4)(0.1)Te(OH)(6) which is crystallized in the monoclinic system with space group P2(1)/c was analyzed at room temperature using X-ray diffractometer data. The unit cell parameters are a = 12.3308(7), b = 7.2011(4), c = 12.0298(8) angstrom, beta = 110.755(4)degrees, V = 998.87(11) angstrom(3) and Z = 4. The final refinement led to R = 0.035 and Rw = 0.038. The main feature of these atomic arrangements is the coexistence of three and different anions (SO42-, SeO42- and TeO66- groups) in the unit cell, connected by hydrogen bonds (O-H center dot center dot center dot O) which make the building of the crystal. The Tl+ and K+ cations, occupying the same positions, are located between these polyhedral. The crystals of Tl1.89K0.11(SO4)(0.9)(SeO4)(0.1)Te(OH)(6) underwent three endothermic peaks at 377, 466 and 472 K. These transitions were detected by DSC and analyzed by dielectric measurements using the impedance and modulus spectroscopy techniques. The IR and Raman spectra recorded at room temperature in the frequency ranges (50-1200) and (400-4000) cm(-1), respectively, have confirmed the presence of TeO66-, SO42- and SeO42- groups in the crystal.