Water uptake and energetics of the formation of barium zirconate based multicomponent oxides.

A group of multi-component oxides based on BaZrO have been prepared using a solid-state reaction method and examined in terms of their water uptake and thermodynamics of formation. Depending on the type and amount of acceptor substitution, the synthesized compounds exhibit various proton defect concentrations, reaching up to 0.2 mol/mol for a compound containing 10 different elements in the B-sublattice, where 50% of them are acceptors.

Energetic Stability and Its Role in the Mechanism of Ionic Transport in NASICON-Type Solid-State Electrolyte LiAlTi(PO).

We apply high-temperature oxide melt solution calorimetry to assess the thermodynamic properties of the material LiAlTi(PO), which has been broadly recognized as one of the best Li-ion-conducting solid electrolytes of the NASICON family. The experimental results reveal large exothermic enthalpies of formation from binary oxides (Δ) and elements (Δ) for all compositions in the range 0 ≤ ≤ 0.5.

Greigite (FeS) is thermodynamically stable: Implications for its terrestrial and planetary occurrence.

Iron sulfide minerals are widespread on Earth and likely in planetary bodies in and beyond our solar system. Using measured enthalpies of formation for three magnetic iron sulfide phases: bulk and nanophase FeS spinel (greigite), and its high-pressure monoclinic phase, we show that greigite is a stable phase in the Fe-S phase diagram at ambient temperature. The thermodynamic stability and low surface energy of greigite supports the common occurrence of fine-grained FeS in many anoxic terrestrial settings.

Disorder in HoTi Zr O: pyrochlore to defect fluorite solid solution series.

Pyrochlore (ABO) is an important, isometric structure-type because of its large variety of compositions and structural derivatives that are generally related to different disordering mechanisms at various spatial scales. The disordering is key to understanding variations in properties, such as magnetic behavior or ionic conduction. Neutron and X-ray total scattering methods were used to investigate the degree of structural disorder in the HoTi Zr O ( = 0.

Conductivity, structure, and thermodynamics of YTiO-YNbO solid solutions.

The defect fluorite yttrium niobate Y3NbO7 and pyrochlore yttrium titanate Y2Ti2O7 solid solutions have been synthesized via a solid state synthesis route. The resulting stoichiometry of the oxides is Y2+xTi2-2xNbxO7, where x = 0 to x = 1. All of the samples were single-phase; however, for those with a predominant fluorite phase, a small amount of additional pyrochlore phase was detected.

Thermochemistry of cation disordered Li ion battery cathode materials, (M' = Nb and Ta, M'' = Mn and Fe).

High temperature oxide melt solution calorimetry studies on (M' = Nb, M'' = Mn and Fe and = 0.20, 0.30 and 0.

Energetics of Formation and Disordering in Rare Earth Weberite RETaO Materials.

The recent finding of local weberite-like ordered domains in disordered and radiation damaged pyrochlore oxides has sparked interest in studying the structure, stability, and order-disorder in compounds that form in the weberite structure. In order to understand the relationships among the energetics, structure, and disordering, weberites of the formula RETaO (RE = La, Nd, Sm-Yb) were synthesized by conventional solid-state techniques. High temperature oxide melt solution calorimetry was used to determine their enthalpies of formation.