1. Physical Properties
Appearance: Orange-yellow to reddish-brown crystalline powder or flaky solid at room temperature.
Density: about 3.357 g/cm3.
Melting point: about 690∘C (decomposition, not completely melted).
Boiling point: about 1750∘C (decomposition, release of oxygen).
Crystal structure: orthorhombic crystal system, lamellar structure, easy to break down into flakes.
2. Chemical Properties
Oxidation: A strong oxidizer, especially at high temperature, can react with reducing substances (e.g., carbon, hydrogen) and reduce to low-valence vanadium oxides (e.g., VO2, V2O3).
Acidity and alkalinity: amphoteric oxide, but predominantly acidic.
Reaction with acids: dissolves in strong acids (e.g. sulfuric acid) to form vanadyloxy ions (VO2+):
V2O5+H2SO4→2VO2++SO42-+H2O
Reaction with bases: dissolves in strong bases (e.g. sodium hydroxide) to form vanadates (e.g. NaVO3):
V2O5+2NaOH→2NaVO3+H2O
Reaction with water: slightly soluble in water to form a weakly acidic solution (pH ≈ 4), forming HVO3 (metavanadate).
