Barium Hydroxide

Barium hydroxide is the salt-like compound of positively charged barium ions each with two negatively charged hydroxide ions. In the crystalline form traded here as an octahydrate, the individual molecules of the substance also contain eight coordinated water molecules.

Barium hydroxide is a polymorphic solid that can exist in different crystalline structures that are either anhydrous or contain different configurations of water molecules. In the form of the octahydrate available from PENPET, barium hydroxide turns into a liquid when heated to 78 °C. If the temperature rises further, the water content gradually boils and the remaining liquid compound decomposes at 600 °C into barium oxide and water. In a vacuum, this point is already reached at 100 °C.

Although the substance's crystals already contain water molecules, it is only slightly soluble in water at room temperature. However, the solubility increases significantly when the mixture is heated. In aqueous solution, barium hydroxide reacts strongly with a pH of 14. The compound is white to colorless. It has no odor of its own.

When stored properly and airtight, the crystalline form of barium hydroxide has a high level of stability. Barium carbonate is formed when it comes into contact with carbon dioxide. The compound is non-flammable, barium hydroxide eventually decomposes into barium oxide and water when heated to high temperatures. Aqueous solutions of the substance can be caustic and corrosive to containers and instruments. As a strong base, barium hydroxide can react violently and dangerously with strong acids. There is a risk of explosion on contact with chlorinated rubber.

Barium hydroxide, especially in aqueous solution, can cause severe irritation and burns. The compound can cause serious eye damage, impairing vision or causing loss of vision. After contact with the substance, the eye should be rinsed immediately under running water. An ophthalmological treatment must then be arranged immediately. Affected areas of skin should also be rinsed thoroughly and given medical attention.

Inhalation of compound dusts and aerosols may cause respiratory irritation. Oral ingestion of barium hydroxide causes severe irritation of the mouth and profuse salivation. Ingestion of the compound can also trigger gastrointestinal symptoms such as diarrhea, vomiting, and nausea. Serious chemical burns and perforations of the esophagus and stomach can also occur. If the compound is absorbed into the metabolism, there is a risk of cardiovascular disorders, impairment of the central nervous system, and muscle paralysis and, in the case of significant amounts, organ damage and kidney failure.

Barium hydroxide is considered to be mildly hazardous to water due to potential harm to aquatic organisms. It should therefore be avoided that the substance penetrates into the environment. In particular, the local authorities must be informed immediately if large quantities escape into the ground, water bodies or waste water. As a corrosive hazardous substance, barium hydroxide is subject to special transport regulations.