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Synthesis, crystal structure, DSC characterization, dielectric and Raman measurements are given for a new mixed solution K0.84(NH4)1.16SO4⋅Te(OH)6 (KNST). X-ray studies showed that the title compound crystallizes in the monoclinic system ( P 2 1 / c ) with the following parameters: a = 14.929 ( 5 ) A , b = 6.558 ( 1 ) A , c = 11.325 ( 1 ) A , β = 120.17 ( 2 ) ° and Z = 4 . The structure can be regarded as being built of isolated TeO6 octahedra, SO4 tetrahedra and K + / NH 4 + cations. The main feature of this structure is the coexistence of two types of hydrogen bonds O H O and N H O ensuring the cohesion of the crystal. Crystals of K0.84(NH4)1.16SO4⋅Te(OH)6 undergo two endothermic peaks at 425 and 480 K and a shoulder at 470 K. These transitions detected by DSC and analyzed by dielectric measurements using the impedance and modulus spectroscopy techniques. Raman scattering measurements on K0.84(NH4)1.16SO4⋅Te(OH)6 material taken between 300 and 620 K are reported in this paper. The spectra indicate clearly two phase transitions. |
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