Vanadyl formate VO(HCOO)2·H2O as a precursor for preparing nanoscale vanadium sesquioxide V2O3.

Vanadyl formate monohydrate VO(HCOO) 2 ·H 2 O has been synthesized by a facile two-stage method. The chemical and structural identity of the synthesized compound has been confirmed by X-ray diffraction, thermogravimetry, vibrational and absorption spectroscopy. It was established that during heating in water and ethylene glycol, VO(HCOO) 2 ·H 2 O leads to vanadyl hydroxide VO(OH) 2 and vanadyl glycolate VO(OCH 2 CH 2 O) being formed. When heated in air or in helium at 300 °C and higher, VO(HCOO) 2 ·H 2 O transforms into vanadium pentoxide or sesquioxide, respectively. VO(HCOO) 2 ·H 2 O was used as a precursor for the synthesis of nanoscale vanadium sesquioxide (with an average particle size of 50 nm), which is stable under the normal conditions and is characterized by a lower metal-insulator transition temperature than the microsized (bulk) compound. The effect of transition temperature reduction for nanoscale vanadium sesquioxide agrees with the lower value of its unit cell volume (V = 296.74 Å3) as compared with that for bulk V 2 O 3 (297.7 Å3). The main factor affecting the V 2 O 3 particle size is the annealing temperature of precursor in inert atmosphere. [ABSTRACT FROM AUTHOR]