Formation of strontium vanadite in SrCO3 - 2VOsub(1.5) system

The process of solid-phase synthesis of strontium vanadite of the composition SrVsub(2)Osub(4+y), where 0(<=)y(<=)0.5 has been studied by the NMR V51 method and X-ray phase analysis. The investigation is conducted in a vacuum with a residual pressure of <10-3 mm Hg in the temperature range of 700-1500 deg C. Synthesis of strontium vanadite proceeds at the highest rate in the temperature range of 950-1100 deg C. At temperatures of >1100 deg C strontium vanadite SrVsub(2)Osub(4.5) disproportionates into Sr6V6O19 and a compound whose composition has not been identified. The formation of strontium vanadite proceeds slowly. After 10 hrs at 1050 deg C the degree of formation of SrV2O4 is 30 mass %. The kinetic curves have a latent period. Stoichiometric strontium vanadite forms only in this system