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
Sterling silver Royal Mint in 1843. It bears the royal stamp "ENRI. REX" ("King Henry") but this was added later, in the reign of Henry III. The first legal definition of sterling silver appeared in 1275, when a statute of Edward I specified that 12 Troy ounces of silver for coinage should contain 11 ounces pennyweights of silver and pennyweights of alloy, with 20 pennyweights to the Troy ounce. This is (not precisely) equivalent to a millesimal fineness of 926. In Colonial America, sterling silver was used for currency and general goods as well. Between 1634 and 1776, some 500 silversmiths created