BaOH28H2O

BaOH28H2O, chemically described as barium hydroxide octahydrate, is the hydrate form of barium hydroxide with eight water molecules of crystallization. The recommended formula is Ba(OH)2·8H2O; the notation BaOH28H2O is sometimes used in line notation. It appears as a white, odorless, crystalline solid.

In terms of properties, Ba(OH)2·8H2O is highly soluble in water and forms strongly alkaline solutions containing Ba2+ and OH−. The octahydrate is typically hygroscopic and readily absorbs moisture from the air, often existing as a concentrated solution in moist environments. Upon heating, it loses water of crystallization to yield anhydrous Ba(OH)2, which is itself highly hygroscopic and reactive with moisture.

Production and occurrence generally involve crystallization from aqueous Ba(OH)2 solutions or preparation by dissolving BaO in water and allowing the solution to crystallize. The octahydrate form is the common laboratory solid encountered for Ba(OH)2, stabilizing as a crystalline hydrate under typical storage conditions.

Applications of Ba(OH)2·8H2O include use as a strong base in laboratory reactions and neutralization processes. In aqueous media, it provides Ba2+ and OH− ions and can be employed to precipitate sulfate as BaSO4 in qualitative analysis. It is sometimes used to prepare standard Ba(OH)2 solutions, though the hydrate’s tendency to lose water on storage means solutions must be periodically standardized.

Safety considerations are important: Ba(OH)2 is caustic and can cause burns; barium compounds are toxic if ingested or inhaled, and solutions should be handled with appropriate PPE. Keep it sealed and away from acids to avoid vigorous reactions.