Reactions between sodium carbonate and vanadium pentoxide

Abstract The isothermal reactions between Na 2 CO 3 (X) and V 2 O 5 (Y) have been studied. It has been noticed that the reaction depends on both temperature and the molar X:Y ratios for the mixtures 1:6 and 1:3. For higher Na 2 CO 3 contents, the reaction is more dependent on temperature. An X-ray examination of the isothermal products revealed the sequence of formation of different types of vanadates. The X-ray diffraction patterns for five sodium vanadates were investigated. The presence of two types of bronze I; Na 2 V 12 O 31 and NaV 6 O 15 was evidenced by both X-ray and differential thermal analysis. The transformation of the former compound to the latter during cooling is accompanied by oxygen evolution; a phenomenon which is reversible.