Copper(II) chlorate heated, giving off a yellow gas, which contains chlorine, oxygen and chlorine dioxide. A green solid is left that is a basic copper salt. Sulfur is highly reactive with copper chlorate, and it is important not to cross contaminate these chemicals, for example in pyrotechnic making. François-Marie Chertier used tetrammine copper chlorate to colour flames blue in 1843. This material was abbreviated TACC with formula Cu(NH)(ClO). TACC explodes on impact. The substance became known as Chertier'c copper for use in blue coloured pyrotechnics. However its deliquescence causes a problem. Mixtures with other metal salts can yield violet or lilac colours
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