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X-ray diffraction, Raman study and electrical properties of the new mixed compound [Rb0.44(NH4)0.56]2HgCl4 · H2O |
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| Authors: | M. Loukil A. Kabadou Ph. Salles A. Ben Salah |
| Affiliation: | a Laboratoire des Sciences des Matériaux et d'Environnement, Faculté des Sciences de Sfax, Sfax 3018, Tunisia b Centre d'Elaboration de Matériaux et d'Etudes Structurales, CNRS, BP 4347, 31055, Toulouse cedex, France |
| Abstract: | Differential scanning calorimetry of [Rb0.44(NH4)0.56]2HgCl4 · H2O material showed three anomalies at 340, 355 and 424 K, respectively. The room temperature phase has space group Pcma (a=8.433(1) Å, b=9.1817(9) Å and c=11.954(1)). Phase II (T=350 K) is disordered and exhibits orthorhombic symmetry (a=8.456(13), b=9.202(9) and c=12.011(10) Å). Hydrogen bonding, the nature and the degree of structure (dis)order and the mechanisms of the transitions are discussed. The dielectric constant ′ at different frequencies and temperature revealed a phase transition at T=340 K related to NH4+ reorientation and H+ diffusion, and a characteristic increase above 355 K, which might be due to loss of water of crystallization. Transport properties in this compound appear to be due to an Rb+/NH4+ and H+ ions hopping mechanism. |
| Keywords: | Author Keywords: Mixed compound Phase transition Raman spectroscopy X-ray |
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