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    • Keywords


      X-ray diffraction; dielectric study; phase transition; DSC; IR absorption; Raman scattering.

    • Abstract


      K$_{0.57}$(NH$_4$)$_{0.43}$CdCl$_3$ and K$_{0.25}$(NH$_4$)$_{0.75}$CdCl$_3$ are orthorhombic, space group Pnma, $Z = 4$, with $a = 8.8760(4)$ $\AA$, $b = 3.9941(2)$ $\AA$, $c = 14.7004(7)$ $\AA$, and $Z = 4$, $a = 8.9567(9)$ $\AA$, $b = 3.9957(4)$ $\AA$, $c = 14.855(2)$ $\AA$, respectively. Final R values are 0.01 and 0.02 for 608 and 834 reflections, respectively. In both the materials, the crystal structure has been determined by X-ray single crystal analysis at room temperature (293 K). The compound structures consist of K$^+$ (or NH$^+_4$) cations and double chains of CdCl$_6$ octahedra sharing one edge extending along $b$-axis. The mixture of KA$^+$/NH$^+_4$ cations are located between the double chains ensuring the stability of the structure by ionic and hydrogen bonding contacts N/K–H$\ldots$ Cl. Spectroscopic, dielectric and differential scanning calorimetry(DSC) measurements were performed to discuss the mechanism of the phase transition. These studies show that these materials, K$_{0.57}$(NH$_4$)$_{0.43}$CdCl$_3$ and K$_{0.25}$(NH$_4$)$_{0.75}$CdCl$_3$, undergo a phase transition at 438 and 454 K, respectively.

    • Author Affiliations



      1. Laboratoire des Sciences des Matériaux et d’Environnement, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, Route de Soukra, 3018 Sfax, Tunisia
    • Dates


© 2017 Indian Academy of Sciences, Bengaluru.