In the synthesis of complex oxides, solid-state metathesis provides low-temperature reactions where product selectivity can be achieved through simple changes in precursor composition. The influence of precursor structure, however, is less understood in solid-state synthesis. Here we present the ternary metathesis reaction (LiMnO 2 + YOCl → YMnO 3 + LiCl) to target two yttrium manganese oxide products, hexagonal and orthorhombic YMnO 3 , when starting from three different LiMnO 2 precursors. Using temperature-dependent synchrotron X-ray and neutron diffraction, we identify the relevant intermediates and temperature regimes of reactions along the pathway to YMnO 3. Manganesecontaining intermediates undergo a charge disproportionation into a reduced Mn(II,III) tetragonal spinel and oxidized Mn(III,IV) cubic spinel, which lead to hexagonal and orthorhombic YMnO 3 , respectively. Density functional theory calculations confirm that the presence of Mn(IV) caused by a small concentration of cation vacancies (∼2.2%) in YMnO 3 stabilizes the orthorhombic polymorph over the hexagonal. Reactions over the course of 2 weeks yield o-YMnO 3 as the majority product at temperatures below 600°C, which supports an equilibration of cation defects over time. Controlling the composition and structure of these defect-accommodating intermediates provides new strategies for selective synthesis of complex oxides at low temperatures.

The chemical reactivity of silicon surface species with LiPF6/carbonate electrolyte are detailed via FTIR spectroscopy and verified by MD/DFPD simulations.

The metastability of Cu4O3 has long hindered the synthetic preparation of bulk samples with substantial crystallinity. The lack of suitable samples has thwarted the detailed understanding of the magnetic properties of Cu4O3 and the ability to tune its properties. While Cu4O3 was recently shown to form in solvothermal reactions, the results are unpredictable, and the crystals are small. We developed a new, more uniform synthesis technique using sealed fused silica tubes. Interrogation of the solid and liquid phases resulting from this reaction has shed more light on the kinetic evolution of copper-containing phases and the microstructural correlation between different precipitation products. We find that direct conversion of the intermediate phase Cu2(NO3)­(OH)3 to Cu4O3 is a likely consequence of dimethylformamide (DMF) triggered in situ reduction. The optimal reduction environment should be more straightforward to attain given the improved reliability of our method, and it remains under investigation. We verify the formation of Cu4O3 via X-ray diffraction, Raman microscopy, and SQUID magnetometry.