The development of new functional materials is essential to the progression of our technology. The syntheses for materials with desired properties are necessary but challenging to control. As an example, rare earth metal molybdenum oxides are a chemical group that offer a variety of physical properties as the molybdenum ion can accommodate different oxidation states. However, literature on this chemical family primarily report on molybdenum oxides with oxidation states of 4+ and higher. A study by the zur Loye group describes an exploratory flux-mediated crystal growth experiment that has been investigated with in situ neutron diffraction.1 Their study emphasizes the process involved in the crystal growth of La4Mo2O11. To control the oxidation state, the researchers used zinc metal as a reducing agent of the system. Interestingly, as the reagent-to-flux ratio changed, different intermediate species with varying molybdenum oxidation states were observed. This talk will elaborate on this study and focus on the control over oxidation states in solid-state syntheses.
(1) Abeysinghe, D.; Huq, A.; Yeon, J.; Smith, M. D.; Zur Loye, H. C. In Situ Neutron Diffraction Studies of the Flux Crystal Growth of the Reduced Molybdates La4Mo2O11 and Ce4Mo2O11: Revealing Unexpected Mixed-Valent Transient Intermediates and Determining the Sequence of Events during Crystal Growth. Chem. Mater. 2018, 30 (3), 1187–1197. https://doi.org/10.1021/acs.chemmater.8b00072.