Structure of [Co(NH3)5CO3]NO3.H2O

Powders of HfO2 doped with various amounts of vanadium were prepared by pyrolysis of oxalic precursors at relatively low temperature (700degreeC). This pyrolysis was carried out under different atmospheres in order to insert vanadium under different oxidation states into hafnia. The various amounts of inserted vanadium into HfO2 were determined by energy dispersive spectroscopy. The powders were structurally characterized by X-ray diffraction, and electron diffraction. Nano particles of monoclinic HfO2 were obtained when incolporating V^5+. The solubility limit in that case was found to be less than 10 at. %. The insertion of vanadium with a lower oxidation state than 5+ led to the stabilization of the cubic phase, with a solubility limit higher than 30% at.