bromide

Bromide refers to the bromide ion, Br−, the conjugate base of hydrobromic acid. In chemical practice it denotes salts formed by bromide with metal cations such as sodium, potassium, or silver. Bromide salts are typically colorless solids and can be highly soluble in water.

Bromide occurs naturally in seawater and saline brines and is extracted from brines or recovered during the refining of bromine. The mineral bromargyrite (silver bromide, AgBr) is a rare natural occurrence. Industrial production often involves neutralizing hydrobromic acid or halogen exchange reactions.

Silver bromide is well known for its role in traditional photography; light exposure converts AgBr to metallic silver, forming an image. In organic synthesis, bromide ions are used as nucleophiles and sources of bromine for selective bromination, with reagents such as N-bromosuccinimide (NBS) being common.

Historically, potassium bromide served as a sedative and anticonvulsant in humans. Its use has declined due to side effects and the availability of safer drugs, though potassium bromide remains used in some veterinary anticonvulsant regimens. Bromide compounds are subject to accumulation and can cause bromism, a toxicity syndrome.

Safety and handling: bromide salts generally exhibit low acute toxicity in humans, but chronic exposure can produce neurologic symptoms, gastrointestinal upset, and cognitive effects. Excretion is primarily via the kidneys, and individuals with renal impairment may experience prolonged effects. Regulatory guidelines govern allowable levels in consumer products and drinking water.