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Structure and characterization of a mixed crystal Rb2SO4.Te(OH)6

1998; Elsevier BV; Volume: 280; Issue: 1-2 Linguagem: Inglês

10.1016/s0925-8388(98)00707-5

1873-4669

Mohamed Dammak, H. Khemakhem, T. Mhiri, A. W. Kolsi, A. Daoud,

Glass properties and applications

Rb2SO4.Te(OH)6 mixed crystals (RTMC) crystallizes in the monoclinic system with space group P21/a and cell parameters: a=11.454(5) Å, b=6.658(4) Å, c=13.636(4) Å, β=107.08°(2), V=994.03(4) Å3, Z=4, Dx=2.918 g cm−3. F(0 0 0)=912, T=298(2) K (room temperature phase), R=0.036 and WR=0.0860 for 1278 observed reflections. The significance of this structure is the presence of both SO42− and TeO66− anions in the same crystal. Differential scanning calorimetry traces show three anomalies at about 414 K, 424 K and 495 K characterizing the three phase transitions in this material. Raman and IR spectra of Rb2SO4.Te(OH)6 mixed crystals (RTMC) recorded at room temperature in the frequency range 10–4000 cm−1, show that the two different anions SO42− and TeO66− coexist in the crystal independently. The bands are in agreement with the monoclinic room temperature phase.