Barium hydroxide Barium hydroxide Barium hydroxide is a chemical compound with the chemical formula Ba(OH)(HO). The monohydrate (x =1), known as baryta or baryta-water, is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form. Barium hydroxide can be prepared by dissolving barium oxide (BaO) in water: It crystallises as the octahydrate, which converts to the monohydrate upon heating in air. At 100 °C in a vacuum, the monohydrate will yield BaO and water. The monohydrate adopts a layered structure (see picture above). The Ba centers adopt a square anti-prismatic geometry. Each Ba center is bound
Calamine brass Calamine brass Calamine brass is brass produced by a particular alloying technique using the zinc ore calamine directly, rather than first refining it to metallic zinc. Direct zinc smelting appears to have been unknown in Europe until the mid-18th century, even though the alloyed calamine brass was in use for centuries, and metallic zinc was produced directly via reducing-atmosphere smelting in India and China from the 12th century CE onwards. Brass is an alloy of copper and zinc and, when it was first developed, methods for producing metallic zinc were unknown. Metallurgists wishing to produce brass thus used calamine (actually