Synthesis of Heavily Hydrated La2NiO4 Through Ion Exchange of Its Fluorinated Derivative: A New Route to the Synthesis of Oxyhydroxide Systems

In this paper we report the synthesis of heavily hydrated La₂NiO₄. While prior literature work has shown that under normal conditions La₂NiO₄ can incorporate very little water, the results here show that samples with high levels (up to 0.6 H₂O per formula unit) can be achieved by first fluorinating La₂NiO₄ and then performing an ion exchange (OH^- for F^-) under hydrothermal conditions. The success of this work highlights the potential of such anion exchange as a novel route of preparing new metastable hydrated (oxyhydroxide) phases.