Synthesis, sintering, electrical properties, and sodium migration pathways of new lyonsite Na$_{2}$Co$_{2}$(MoO$_{4})_{3}$

Authors

Rawia Nasri
RIADH MARZOUKI
SAMUEL GEORGES
SAID OBBADE
MOHAMED FAOUZI ZID

DOI

10.3906/kim-1801-89

Abstract

A new double molybdate Na$_{2}$Co$_{2}$(MoO$_{4})_{3}$ was synthesized via solid-state reaction and characterized by single-crystal X-ray diffraction (XRD). This compound is a new member of the lyonsite structure type. It crystallized in the orthorhombic system, space group Pnma with cell parameters $a$ = 5.272(2) Å, $b$ = 10.816(3) Å, and $c$ = 18.064(3) Å. The structure can be described as a three-dimensional framework with hexagonal tunnels in which the Na$^{+}$ cations lie. The obtained structural model is supported by charge distribution analysis and bond valence sum validation tools. Fourier-transform infrared spectroscopy and scanning electron microscopy analyses were carried out. Ball milling was used to reduce the particle size of the synthesized powder. Dense ceramics with a relative density of 78% were obtained by sintering at 853 K. The conductivity of the title compound was studied for different relative densities. The ionic conductivity at 723 K with an activation energy of 1.2 eV was 3.24 $\times $ 10$^{-6}$ S cm$^{-1}$. The bond valence sum map model is used to simulate the cation migration pathways in the anionic framework.

Keywords

Solid state reaction, lyonsite, sintering, electrical properties

First Page

1251

Last Page

1264

Recommended Citation

Nasri, Rawia; MARZOUKI, RIADH; GEORGES, SAMUEL; OBBADE, SAID; and ZID, MOHAMED FAOUZI (2018) "Synthesis, sintering, electrical properties, and sodium migration pathways of new lyonsite Na$_{2}$Co$_{2}$(MoO$_{4})_{3}$," Turkish Journal of Chemistry: Vol. 42: No. 5, Article 5. https://doi.org/10.3906/kim-1801-89
Available at: https://journals.tubitak.gov.tr/chem/vol42/iss5/5