Protonic conduction of CsH2PO4 and its composite with silica in dry and humid atmospheres

Characterization of electrical properties of Pb-modified BaSnO3 using impedance spectroscopy

Impedance spectroscopy and dielectric analysis in KH2PO4 single crystal

High-temperature behavior of CsH2PO4 and CsH2PO4-SiO2 composites

X-ray diffraction, thermogravimetric (TGA), differential scanning calorimetric (DSC), and impedance analysis were used to study the reported high-temperature phase transitions at 107, 149, 230, and 256 °C in crystals of cesium dihydrogen phosphate, CsH2PO4 (CDP). Our results show strong evidence that at all these temperatures, the observed DSC or differential thermal analysis (DTA) endothermic effects appear only as a consequence of a dehydration process starting on the surface of the crystal. Our results thus show that the reported transition at 230 °C is not a polymorphic transition. This means that the monoclinic symmetry, stable at room temperature, with space group P21/m–C2k2, is maintained up to the final decomposition. Moreover, since we have not found any evidence for the existence of a superprotonic high-temperature phase above 230 °C, the high conductivity above 230 °C is thus only a consequence of the dehydration of the crystal surface.

A. Vargas

Papers

On the reported high-temperature phase transition in KH2PO4—strong evidence of partial polymerization instead of a structural phase transition