Synthesis, crystal structure, spectroscopic and magnetic properties of strontium oxovanadium(IV) tartrate: molecular precursor for SrVO3

Abstract

A new alkaline-earth-metal oxovanadium(IV) tartrate dimer with formula [Sr(VO)((±)-C₄H₂O₆)(H₂O)₃]₂ has been synthesized and characterized. The crystal structure consists of a three-dimensional (3D) arrangement of [(VO)((±)-C₄H₂O₆)]₂^4– dimeric anions, strontium cations and water molecules. There are several bonds between the oxygen atoms of the dimeric anions and the strontium cations, including a bond with the oxygen of the vanadyl group. The electron paramagnetic resonance (EPR) measurements show the dimeric nature of this complex. Thermal treatments of the compound, at low temperatures, yield different mixed oxides depending on the atmosphere employed. In air at 500 °C only the α-pyrovanadate is obtained while a thermal treatment in a hydrogen atmosphere at 900 °C is needed in order to obtain the SrVO₃ oxide. The magnetic susceptibility of the SrVO₃ phase revealed its metallic character.