KBr

Potassium bromide (KBr) is an inorganic salt composed of potassium ions (K+) and bromide ions (Br−). It appears as a white, odorless, crystalline solid that is highly soluble in water. In the solid state, KBr adopts the same rock-salt crystal structure as other alkali metal halides and has a relatively high melting point.

KBr is typically produced by the neutralization of hydrobromic acid with a potassium salt, for example: K2CO3 + 2 HBr → 2 KBr + CO2 + H2O. It can also be obtained from brine sources containing potassium and bromide ions, followed by purification. The compound is used commercially in a range of chemical and industrial applications, and its production is linked to sources of bromide in natural brines and mineral deposits.

Applications of KBr include its historical and ongoing roles in medicine, photography, and analytical chemistry. In medicine, potassium bromide was once widely used as a sedative and anticonvulsant; it is now largely superseded for human use but remains employed in some veterinary anticonvulsant formulations. In photography, KBr has been used in the preparation of photographic emulsions and as a component of reagents. In infrared spectroscopy, potassium bromide is valued for its transparency to infrared radiation; it is pressed into pellets or used as a window material to support IR analyses.

Safety and handling considerations are important with KBr. Ingestion or chronic exposure can lead to bromide poisoning (bromism), which may affect the nervous system and skin. It is corrosive to tissues in high concentrations and should be handled with appropriate protective equipment. Environmental exposure should be minimized, as soluble bromides can impact aquatic ecosystems.