Synthesis and characterisation of ternary molybdates AgZn3R(MoO4)5 (R = In, Fe)

Abstract

An important role in the study and the obtaining of new phases with valuable physical and chemical properties is taken by ternary compounds with a tetrahedral anion containing various combinations of mono- and multivalent cations, including ternary molybdates and tungstates. Silver ternary molybdates AgA3R(MoO4)5 with the NaMg3In(MoO4)5 structural type (triclinic crystal system, space group P1, Z = 2) are of particular interest and have a high ion conductivity (10–3–10–2 S/cm). In this regard, the aim of this work was to reveal the possibility to form similar compounds in silver, zinc, indium, and iron molybdate and tungstate systems and to determine the effect of the nature of tetrahedral anion and three-charged cations on their obtaining and properties. Polycrystalline samples were synthesized using a ceramic technology and studied by differential thermal (DTA) and X-ray diffraction analysis (XRD). The research resulted in obtaining a new ternary molybdates AgZn3R(MoO4)5 (R = In, Fe) crystallising in the triclinic crystal system (space group P1, Z = 2). The sequence of chemical transformations that occur during the formation of these compounds, their crystallographic and thermal characteristics were determined. Unit cell parameters for the indium compound are as follows: a = 6.9920(4), b = 7.0491(4), c = 17.9196(9) Å, a = 87.692(5), b = 87.381(5), g = 79.173(5)°; and for the iron compound: a = 6.9229(3), b = 6.9828(4), c = 17.7574(8) Å, a = 87.943(4), b = 87.346(5), g = 78.882(5)°. It was established that silver-containing ternary zinc tungstates with indium and iron with a similar structure are not formed.

Keywords

• ternary molybdates
• silver
• tungsten
• solid-state synthesis
• x-ray diffraction analysis (xrd)
• thermal properties.