TCC’s Ammonium Bromide, NH4Br, is the ammonium salt of hydrobromic acid. The chemical crystallizes into colorless prisms, possessing a saline taste. It sublimes on heating and is easily soluble in water. On exposure to air it gradually assumes a yellow color because of the oxidation of traces of bromide (Br–) to bromine (Br2). Ammonium bromide is used for photography in films, plates and papers; in fireproofing of wood; in lithography and process engraving; in corrosion inhibitors; and in pharmaceutical preparations.
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The Chemical Company’s Ammonium Bromide (NH4Br) is a white to colorless crystalline powder with a saline taste and faint ammonia odor. It is the ammonium salt of hydrobromic acid, formed by the direct reaction of ammonia with hydrogen bromide. Ammonium Bromide is slightly hygroscopic and gradually turns yellow upon prolonged exposure to air due to the oxidation of trace bromide ions to free bromine. It is freely soluble in water and methanol, slightly soluble in ethanol, and practically insoluble in acetone and ethyl acetate.
Ammonium Bromide is a well-established industrial and specialty chemical with a long history of use across photography, pharmaceuticals, flame retardants, and industrial water treatment. It is valued as a reliable, cost-effective source of the bromide ion across a wide range of chemical processes and formulations. Its relatively mild handling profile compared to liquid bromine or hydrobromic acid makes it a practical choice for applications requiring controlled bromide delivery.
Ammonium Bromide sublimes at 452°C at atmospheric pressure and at just 235°C under vacuum, without passing through a true liquid phase under normal conditions. Upon heating, it dissociates reversibly into ammonia (NH3) and hydrogen bromide (HBr) gases — a property exploited in certain vapor-phase deposition and purification processes. It is an acid salt: the ammonium ion hydrolyzes slightly in water, giving aqueous solutions a mildly acidic pH with a pKa of approximately 5.
In the early 20th century, ammonium bromide was widely prescribed as a sedative and anticonvulsant for the treatment of epilepsy and nervous conditions — one of the first inorganic compounds used therapeutically in modern medicine. While largely superseded by modern antiepileptic drugs in human medicine, bromide salts including ammonium bromide remain in use in veterinary medicine for the management of canine epilepsy. In photography, ammonium bromide served as a key restrainer in alkaline photographic developers, suppressing fog and improving image contrast.
| Property | Value |
| Molecular Formula | NH4Br |
| Molecular Weight | 97.94 g/mol |
| Appearance | White to colorless crystalline powder or granules |
| Odor | Faint ammonia odor; essentially odorless when pure |
| Density | 2.43 g/cm³ |
| Sublimation Point | 452°C (atmospheric); 235°C (under vacuum) |
| Decomposition | Dissociates reversibly to NH3 and HBr on heating |
| Solubility in Water | 78.3 g/100 mL at 25°C; 145.6 g/100 mL at 100°C |
| Solubility in Alcohol | Slightly soluble in ethanol; freely soluble in methanol |
| Solubility in Acetone/Ether | Slightly soluble in ether; practically insoluble in acetone |
| pH (aqueous solution) | Mildly acidic; pKa ≈5 (ammonium ion hydrolysis) |
| Crystal Structure | Colorless rhombic (orthorhombic) prisms |
| Air Stability | Slightly hygroscopic; yellows on prolonged air exposure |
| Incompatibilities | Strong acids, bromine trifluoride, bromine trichloride, most metals |
| UN Number | Not classified as dangerous goods for transport |
| Available Grades | Technical, Reagent (ACS), USP/NF, High Purity (99.999%) |
TCC’s Ammonium Bromide is used for photography in films, plates and papers; in fireproofing of wood; in lithography and process engraving; in corrosion inhibitors; and in pharmaceutical preparations. Ammonium Bromide used in combination with an appropriate oxidizer is an efficient biocide, applied in various industrial water systems and waste water, to control bacteria, fungi and algae.
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