Barium nitrate fighters, such as the Hawker Hurricane and Supermarine Spitfire, during the Battle of Britain. It is also used in the manufacturing process of barium oxide, the vacuum tube industry and for green fire in pyrotechnics. Like all soluble barium compounds, barium nitrate is toxic by ingestion or inhalation. Solutions of sulfate salts such as Epsom salts or sodium sulfate may be given as first aid for barium poisoning, as they precipitate the barium as the insoluble (and non-toxic) barium sulfate. Inhalation may also cause irritation to the respiratory tract. While skin or eye contact is less harmful than ingestion or
Barium titanate has been shown to produce a bulk material with a higher viscoelastic stiffness than that of diamonds. Barium titanate goes through two phase transitions that change the crystal shape and volume. This phase change leads to composites where the barium titanates have a negative bulk modulus (Young's modulus), meaning that when a force acts on the inclusions, there is displacement in the opposite direction, further stiffening the composite. Like many oxides, barium titanate is insoluble in water but attacked by sulfuric acid. Its bulk room-temperature bandgap is 3.2 eV, but this increases to ~3.5 eV when the particle size is