• K Byrappa

Articles written in Bulletin of Materials Science

• Ionic conductivity and hopping rate data for some NASICON analogues

The a.c. conductivity of ionic materials shows two regions of frequency-dependent conductivity over a wide range of frequencies. Jonscher’s law of dielectric response for ionic conductors enables us to characterize the conductivities. The region of low frequency dispersion approximates to a frequency-independent plateau enabling us to obtain the d.c. conductivity. In some other conductors, the presence of low-frequency dispersion cannot be neglected while determining the effective d.c. conductivity. We have used this method to extract the d.c. conductivity and hopping rate as well as to estimate concentrations of the mobile ions (carriers) in some NASICON analogues.

• Conductivity pre-exponential factors for some new superionic conductors

The pre-exponential factors obtained from the ionic conductivity studies on Na2(La, Al)ZrP3O12, Na2(La, Al)TiP3O12, NH4Zr2V3O12 and AlPO4:Li+ have been analysed. The compensation law has been found to be valid for these materials indicating that the entropy is directly related to the activation energy. The 1/α vsβ plots show straight lines for most of the superionic materials except for a few and this variation has been discussed.

• NH4Zr2V3O12 proton conductor

NH4Zr2V3O12, a new proton conductor, has been synthesized by flux, melt and hydrothermal methods. The crystals were subjected to X-ray diffraction, differential thermal analysis, infrared spectroscopy and impedance measurements.

• X-ray structure, hydrogen bonding and lattice energy analysis of (2$E$)-1-(anthracen-9-yl)-3-(4-substitutedphenyl)prop-2-en-1-ones

(2$E$)-1-(anthracen-9-yl)-3-(4-chlorophenyl)prop-2-en-1-ones and (2$E$)-1-(anthracen-9-yl)-3-(4-nitrophenyl) prop-2-en-1-ones crystallize in the monoclinic crystal system with space group P2$_1$/c. Single-crystal X-ray diffraction data for both the compounds were collected on an X’Calibur CCD area detector diffractometer (Oxford Diffraction)using Mo$K\alpha$ radiation ($\lambda = 0.7107$ $\AA$) at 293(2) K. The crystal structures were solved by direct methods and refined by full-matrix least-square procedures to a final $R$ value of 0.0468 [I] and 0.0486 [II]. The crystal structures as elucidated by X-ray diffraction methods show the presence of a few intermolecular interactions, and the nature and energetics associated with these interactions have been characterized using PIXEL software.

• # Bulletin of Materials Science

Current Issue
Volume 42 | Issue 6
December 2019

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019