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      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/039/05/1147-1156

    • 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

       

      ABDESSATTAR BEN CHRIFA1 ABDELHAMID BEN SALAH1 MOHAMED LOUKIL1

      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.