Related Experiment Video
Updated: Jun 17, 2026

Determination of Thermodynamic Properties of Alkaline Earth-liquid Metal Alloys Using the Electromotive Force Technique
Published on: November 3, 2017
Thermal stability of alkali and alkaline-earth substituted LAMOX oxide-ion conductors
1Laboratoire des Oxydes et Fluorures, UMR CNRS 6010, Université du Maine, Avenue Olivier Messiaen, 72085 Le Mans cedex 9, France.
Abstract:
The high temperature demixing/recombination phenomenon previously observed in Ca-substituted La(2)Mo(2)O(9) oxide ion conductors [A. Selmi et al., Solid State Ionics, 2006, 177, 3051; Eur. J. Inorg. Chem., 2008, 1813] has been visualised using scanning electron microscopy and EDX analysis. The demixed state appears as CaMoO(4) straight solid streams erupted from pores within LAMOX grains. The thermal stability study is extended to other alkali and alkaline-earth substituted LAMOX compounds, all of which are shown, in temperature-controlled X-ray diffractograms, to present similar demixing/recombination processes. The most spectacular effect is observed in La(1.88)K(0.12)Mo(0.6)W(1.4)O(8.88) where demixing takes the form of a total decomposition, before full recombination at a higher temperature. Such a phenomenon is interpreted as originating from temperature-dependent solid solution limits with higher substitutional ranges at higher temperatures. It results in the metastabilisation of pure phases by quenching (or rapid cooling), whereas the stable state is demixed, as shown on slowly cooled samples.
Related Concept Videos
Alkali Metals
Table 1: Properties of the alkali metals
Weak Acid Solutions
Trends in Lattice Energy: Ion Size and Charge
Properties of Transition Metals
Lattice Energies of Ionic Crystals
Complexation Equilibria: Factors Influencing Stability of Complexes

