Ferric bromide (10031-26-2) Physical and Chemical Properties
Ferric bromide
An inorganic iron(III) bromide salt used as a Lewis acid catalyst and brominating reagent in synthesis and process chemistry; typically supplied as a moisture‑sensitive, corrosive solid requiring controlled handling.
| CAS Number | 10031-26-2 |
| Family | Iron halides / inorganic bromide salt |
| Typical Form | Powder or crystalline solid |
| Common Grades | EP |
Ferric bromide is an inorganic iron(III) halide belonging to the class of metal bromides; its stoichiometric composition is given by the molecular formula \(\ce{Br3Fe}\). Structurally it is best described as the combination of a high-charge-density iron(III) center and three bromide anions. The \(\ce{Fe^{3+}}\) centre is a hard Lewis acid with a strong propensity for coordination and hydrolysis; bromide is a relatively soft, singly charged halide anion that provides weakly coordinating character relative to more strongly donating ligands. The computed descriptors show zero hydrogen-bond donors and a small acceptor count consistent with an inorganic salt rather than an organic covalent molecule.
In condensed phases the compound behaves as a polar ionic material that is chemically reactive toward nucleophiles and protic media. Aqueous contact leads to hydrolysis of the iron(III) centre and formation of acidic iron hydroxo/bromo species and hydrobromic acid; this hydrolysis dominates the observed solution chemistry and strongly influences stability, corrosivity and compatibility. As a Lewis acid, ferric bromide is used in heterogeneous and homogeneous catalytic roles where electrophilic activation or bromination is required; its redox and halogen chemistry also make it relevant in synthetic and reagent contexts.
Common commercial grades reported for this substance include: EP.
Basic Physical Properties
Density
No experimentally established value for this property is available in the current data context.
Melting or Decomposition Point
No experimentally established value for this property is available in the current data context.
Solubility in Water
Ferric bromide is an ionic bromide and will dissolve in polar solvents; however, solubility in water is complicated by rapid hydrolysis of the \(\ce{Fe^{3+}}\) centre. In water the salt does not behave as a simple inert electrolyte: hydrolysis produces hydrobromic acid and iron-containing hydroxo/bromo species, and the apparent solubility and speciation are therefore pH- and concentration-dependent. In organic polar solvents (e.g., halogenated solvents, acetonitrile) solvation of the ion pair or coordination of solvent molecules to iron can increase apparent solubility relative to water.
Solution pH (Qualitative Behavior)
Aqueous solutions of ferric bromide are acidic due to hydrolysis of \(\ce{Fe^{3+}}\), which generates protonated species and liberates hydrobromic acid. The pH will be strongly acidic at modest concentrations; the exact pH depends on concentration, temperature and the extent of hydrolysis and complexation. No single numerical solution pH is available in the current data context.
Chemical Properties
Acid–Base Behavior
The dominant acid–base character is Lewis acidity associated with \(\ce{Fe^{3+}}\). In protic solvents \(\ce{Fe^{3+}}\) undergoes stepwise hydrolysis to give species such as \(\ce{Fe(OH)^{2+}}\), \(\ce{Fe(OH)2^{+}}\) and polymeric iron hydroxo species, with concomitant release of protons (increasing acidity). Bromide acts as a weakly coordinating counter-anion and is not a significant Brønsted base in this context. In nonaqueous media the iron center can accept electron density from donor solvents or ligands, modifying Lewis acidity and reactivity.
Reactivity and Stability
Ferric bromide is moisture-sensitive and chemically reactive toward nucleophiles and reducing agents. Contact with water leads to hydrolysis and acid formation; contact with strong reducing agents can reduce iron(III) to lower oxidation states and can liberate bromine or bromide species. The material is corrosive and can cause severe burns on contact. Thermal stability is limited relative to inert inorganic salts; upon heating or under strongly reducing/oxidizing environments, decomposition and release of bromine-containing vapours are possible. Stored material should be kept dry and segregated from incompatible substances (strong reducers, bases, and materials that react violently with acids or oxidizers).
Molecular and Ionic Parameters
Formula and Molecular Weight
- Molecular formula: \(\ce{Br3Fe}\)
- Molecular weight: 295.56 \(\mathrm{g}\,\mathrm{mol}^{-1}\)
- Exact mass: 294.68790
- Monoisotopic mass: 292.68995
Additional computed descriptors:
- Hydrogen bond donor count: 0
- Hydrogen bond acceptor count: 3
- Rotatable bond count: 0
- Topological polar surface area (TPSA): 0
- Heavy atom count: 4
- Formal charge (overall): 0
Constituent Ions
The compound consists of the ferric cation and bromide anions: \(\ce{Fe^3+}\) and \(\ce{Br-}\). The ionic nature governs much of the compound's solubility, reactivity and corrosivity.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS number: 10031-26-2
- Deprecated CAS: 12258-65-0
- EC number: 233-089-1
- UNII: 9RDO128EH7
- DSSTox Substance ID: DTXSID40894107
Additional identifiers present in supplier and registry lists include various internal and registry codes; the principal unique registry identifier commonly used for procurement and specification is the CAS number shown above.
Synonyms and Common Names
Common and recorded names/synonyms include:
- Ferric bromide
- Iron bromide (\(\ce{FeBr3}\)) — presented in source synonym strings (formatted here to comply with chemical formula notation)
- IRON (III) BROMIDE
- Iron tribromide
- iron(3+);tribromide
- \(\ce{Br3Fe}\)
- iron(3+) tribromide
- Ferric Bromide; Iron Tribromide; Iron(III) Bromide
Structural identifiers:
- SMILES: [Fe+3].[Br-].[Br-].[Br-]
- InChI: InChI=1S/3BrH.Fe/h3*1H;/q;;;+3/p-3
- InChIKey: FEONEKOZSGPOFN-UHFFFAOYSA-K
Industrial and Commercial Applications
Functional Roles and Use Sectors
Ferric bromide functions principally as a Lewis acid and as a bromination reagent. It is used in fine chemical and specialty-organic synthesis where electrophilic bromination or Lewis-acid activation of substrates is required. Its ability to activate aromatic substrates toward electrophilic substitution makes it useful in synthetic methodologies in laboratory and industrial settings.
Typical Application Examples
- Lewis-acid catalyst for bromination and halogenation of aromatic compounds.
- Reagent in organic synthesis to generate brominated intermediates or to activate substrates for further functionalization.
- Use is typically in controlled, small-scale operations in synthetic laboratories or processes where corrosive, acidic reagents are handled with appropriate engineering controls.
Safety and Handling Overview
Health and Environmental Hazards
Hazard classifications and statements reported in manufacturing and supplier communications indicate significant acute and corrosive hazards:
- H302 (10.9%): Harmful if swallowed.
- H314 (13%): Causes severe skin burns and eye damage.
- H315 (87%): Causes skin irritation.
- H319 (87%): Causes serious eye irritation.
- H335 (87%): May cause respiratory irritation.
Toxicological considerations derive both from the bromine/bromide chemistry and from iron(III) toxicity: bromine-related species are strong oxidizers and can cause mucous-membrane damage; hydrolysis products (hydrobromic and bromic acids) contribute to corrosive effects. Chronic or large systemic exposure to bromide can produce neurological effects (bromism) characterized by central nervous system depression and neuropsychiatric symptoms. Routes of significant exposure include inhalation of dusts or vapours, dermal contact and ingestion.
First-aid highlights:
- EYES: Flush with running water for several minutes; seek medical attention.
- SKIN: Rinse affected area with copious water for at least 15 minutes; remove contaminated clothing and seek medical attention.
- INGESTION: Do not induce vomiting; rinse mouth and seek immediate medical advice.
- INHALATION: Remove to fresh air; provide artificial respiration if required and seek medical attention.
For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
Storage and Handling Considerations
Store ferric bromide in tightly closed containers in a cool, dry, well-ventilated area away from moisture and incompatible materials (strong reducing agents, strong bases, and reactive metals). Use appropriate corrosion-resistant containers and transfer equipment. Handling should be performed with suitable personal protective equipment (chemical-resistant gloves, eye/face protection, protective clothing) and engineering controls to limit dust and vapour exposure (local exhaust ventilation, closed transfer). Spill and waste handling should treat material as corrosive and potentially oxidizing; segregate from incompatible waste streams.
For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
