Barium bromide and can cause severe poisoning if ingested. Barium bromide Barium bromide is the chemical compound with the formula BaBr. Like barium chloride, it dissolves well in water and is toxic in aqueous solution. BaBr crystallizes in a lead chloride motif, giving white orthorhombic crystals which are deliquescent. In aqueous solution BaBr behaves as a simple salt. Barium bromide reacts with the sulfate ion from sulfuric acid to produce a precipitate of barium sulfate. Similar reactions occur with oxalic acid, hydrofluoric acid, and phosphoric acid. Barium bromide can be prepared from barium sulfide or barium carbonate via reaction with hydrobromic acid
Chemical element plants, the calcium in mollusc shells, or the iron in the hemoglobin in vertebrate animals' red blood cells. The concept of an "element" as an undivisible substance has developed through three major historical phases: Classical definitions (such as those of the ancient Greeks), chemical definitions, and atomic definitions. Ancient philosophy posited a set of classical elements to explain observed patterns in nature. These "elements" originally referred to "earth", "water", "air" and "fire" rather than the chemical elements of modern science. The term 'elements' ("stoicheia") was first used by the Greek philosopher Plato in about 360 BCE in his dialogue Timaeus,