Structural and conductivity studies of CsKSO4Te(OH)6 and Rb1.25K0.75SO4Te(OH)6 materials

N. Chabchoub (1) , Jacques Darriet (2) , Hamadi Khemakhem (1)

1 LPA - Laboratoire de Physique Appliquée [Université de Sfax]
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

The crystal structures of the title compounds were solved using the single-crystal X-ray diffraction technique. At room temperature CsKSO4Te(OH)6 was found to crystallize in the monoclinic system with Pn space group and lattice parameters: a =12.5463(6)A˚ ; b = 6:5765(2) A˚ ; c =12:6916(7) A˚ ; b =106:53(2)1; V = 1003:914(4)˚A3 ; Z =4 and Dcalc= 3.29 g/cm3. The structural refinement has led to a reliability factor of R1=0.0284 (wR2=0.064) for 7577 independent reflections. Rb1.25K0.75SO4Te(OH)6 material possesses a monoclinic structure with space group P21/a and cell parameters: a =11.3411(6)A˚ ; b =6.5819(2)A˚ ; c =13.5730(8)A˚ ; b =106.860(10)°; V =969.62(10)˚A3 ; Z =4 and D =3.16(3) g/cm3. The residuals are R1=0.0297 and wR2=0.0776 for 3336 independent reflections. The main interest of these structures is the presence of two different and independent anionic groups (TeO66− and SO42−) in the same crystal. Complex impedance measurements (Z*=Z′—iZ″) have been undertaken in the frequency and temperature ranges 20–106 Hz and 400–600 K, respectively. The dielectric relaxation is studied in the complex modulus formalism M*.

Mots clés: Sulfate tellurate; Crystal structure; X-ray diffraction; Modulus formalism

Domaines: Matériaux

N. Chabchoub, Jacques Darriet, Hamadi Khemakhem. Structural and conductivity studies of CsKSO4Te(OH)6 and Rb1.25K0.75SO4Te(OH)6 materials. Journal of Solid State Chemistry, 2006, vol. 179, n° 7, p. 2164-2173. ⟨10.1016/j.jssc.2006.04.020⟩. ⟨hal-00085461⟩