Hydrothermal Synthesis of Lead Oxide Carboxylate Single Crystals

Science Center, Bent Corridor

Symmetry is one of the most prominent aspects of crystal structures and can determine the different properties compounds exhibit. In a world where highly symmetrical structures are common, synthesizing compounds of low symmetry has become an important endeavor due to their unique properties. In particular, structures that are non-centrosymmetric can give rise to novel optical properties, such as the ability to change the frequency of light. Our work has included synthesizing lead oxide carboxylates, a family of hybrid inorganic-organic compounds that have the potential to exhibit non-centrosymmetric structures. Thus far, we have worked with phenylacetic acid, α-methoxyphenylacetic, and methylsuccinic acid as the carboxylate ligands in order to determine how these organic components, as well as the inorganic component of lead oxide, influence the overall symmetries of the compounds. Results include the hydrothermal reaction of lead oxide and phenylacetic acid to yield Pb6O2(C8H7O2)8, a new lead oxide carboxylate phase that exhibits low symmetry. Factors considered when optimizing synthetic procedures included stoichiometry, solvent ratios, temperature, and pH. Powder X-ray diffraction, single crystal X-ray diffraction, and thermogravimetric analysis were utilized for characterization of the products.