Microwave dielectric relaxation of water in hydrated melts: system Ca(NO3)2.4H2O

✍ Scribed by H. Farber; S. Petrucci

• Publisher: Elsevier Science
• Year: 1981
• Weight: 327 KB
• Volume: 20
• Category: Article
• ISSN: 0378-4487
• DOI: 10.1016/0378-4487(81)80055-6

✦ Synopsis

The microwave complex permittivities of hydrated melts of composition Ca(N03)2 3.9 H20, in the frequency range 8.2-79 GHz, and temperature range 40-SS'C, are reported. The real and imaginarry coefficients of the complex permittivity show a dielectric relaxation process, which can be described in most of the frequency range by a Debye function for a single relaxation. Some deviation becomes apparent, however, at the upper end of the frequency range investigated. Eyring plots of the inverse of the relaxation time vs the inverse of temperature give the activation parameters for the process. The latter is interpreted as due to the rotation of water in the melts, all the water being probably coordinated with the cations. Compared to the activation parameters in pure water one notices an increase in both the enthalpy and entropy of activation. An increase in the activation energy in concentrated aqueous LiCl has been already reported in the literature..