S. Kamoun

Phase transition and analysis of AC conductivity data of the (Cs)0.26(Rb)0.74H(SO4)0.89(SeO4)0.11 compound

Abstract The X-ray diffraction, vibrational and impedance spectroscopy studies of (Cs) 0.26 (Rb) 0.74 H(SO 4 ) 0.89 (SeO 4 ) 0.11 (CsRbHSSe) new solid solution are presented. The title compound undergo a superionic phase transition (SPT) at T=395 K . This transition was confirmed by an abrupt increase of conductivity. The bulk impedance parameters of CsRbHSSe, RbH(SO 4 ) 0.81 (SeO 4 ) 0.19 (RbHSSe) and CsH(SO 4 ) 0.76 (SeO 4 ) 0.24 (CsHSSe) were determined from an analysis of AC conductivity data measured in a wide temperature range. The charge carriers concentration in the samples investigated has been evaluated using the Almond–West formalism and shown to be independent of temperature.

Crystal structure, NMR spectroscopy, electrical properties of catena-poly[(bis-glycinium-k2 O:O)-di-μ-thiocyanate- k2 N:S; k2 S:N -cadmium (II)]

The crystal structure, the 111Cd and 13C NMR spectroscopy, and the complex impedance have been carried out on a new polymeric hybrid compound: [Cd(NH3CH2COO)2(SCN)2]n. Crystal structure shows that in the title compound the cadmium atoms have a 2N2S2O-hexa-coordination sphere, exhibiting pseudo-octahedral geometry. The cadmium atoms are bridged by two thiocyanate ions generating 1D polymeric chains. 111Cd and 13C MAS NMR spectroscopy show multiplets that result from 111Cd, 14N and 13C, 14N spin–spin coupling, respectively. The AC impedance measurements were performed as a function of both frequency and temperature. The AC and DC electrical conduction have been studied. The activation energy associated with the bulk resistance determined from equivalent circuit was found close to that of the activation energy obtained from DC conductivity. The conduction mechanisms are attributed to the correlated barrier hopping model.

Structural and vibrational study of a new protonic conductor (Cs)0.26(Rb)0.74H(SO4)0.89(SeO4)0.11

Abstract The crystal structure of (Cs) 0.26 (Rb) 0.74 H(SO 4 ) 0.89 (SeO 4 ) 0.11 (CsRbHSSe) has been determined by X-ray single-crystal analysis. This compound crystallizes in the space group Pc with unit cell dimensions a=14.733(4) A , b=4.6437(9) A , c=15.102(4) A , β =120.94(3)°, and Z =8. The refinement converged to R =0.0391 and wR 2 =0.0964. The mixed compound CsRbHSSe is a chain-based structure. The Cs + and Rb + cations are intercalated between chains of HBO 4 − (B=S, Se) groups linked with O–H⋯O hydrogen-bonding. CsRbHSSe presents a new type of structural arrangement different from RbH(SO 4 ) 0.81 (SeO 4 ) 0.19 (RbHSSe) and CsH(SO 4 ) 0.76 (SeO 4 ) 0.24 (CsHSSe). Infrared (IR) and Raman spectroscopic studies were performed to confirm results of the radiocrystallographic method.