Bromine (Br)
halogenLiquid
Peso atomico standard
79,904 u [79,901, 79,907]Configurazione elettronica
[Ar] 4s2 3d10 4p5Punto di fusione
-7,2 °CPunto di ebollizione
58,8 °CDensità
3102,8 kg/m³Stati di ossidazione
−1, +1, +2, +3, +4, +5, +7Elettronegatività (Pauling)
2,96Energia di ionizzazione (1ª)
11,81381 eVAnno della scoperta
1825Raggio atomico
115 pmDettagli
Bromine is a halogen, group 17 element, and the only nonmetal that is liquid near room temperature. Elemental bromine occurs as diatomic Br₂ and is a dense, volatile, strongly oxidizing substance. In nature bromine is found mainly as bromide ions in seawater, salt lakes, and subsurface brines. Its chemistry is intermediate between chlorine and iodine, with important roles in flame retardants, drilling fluids, pharmaceuticals, and photographic chemistry.
Bromine is the only nonmetallic liquid element. It is a heavy, mobile, reddish-brown liquid, volatilizing readily at room temperature to a red vapor with a strong disagreeable odor, resembling chlorine, and having a very irritating effect on the eyes and throat; it is readily soluble in water or carbon disulfide, forming a red solution, is less active than chlorine but more so than iodine; it unites readily with many elements and has a bleaching action; when spilled on the skin it produces painful sores. It presents a serious health hazard, and maximum safety precautions should be taken when handling it.
The name derives from the Greek bromos for "bad stench" or "bad odour". It was first prepared by the German chemist Carl Löwig in 1825, but it was first publicly announced in 1826 by the French chemist and pharmacist Antoine-Jérôme Balard, and so the discovery is, therefore, credited to him.
The only nonmetallic element that is a liquid at normal room temperatures, bromine was produced by Carl Löwig, a young chemistry student, the summer before starting his freshman year at Heidelberg. When he showed his professor, Leopold Gmelin, the red, smelly liquid he had produced, Gmelin realized that this was an unknown substance and encouraged Löwig to produce more of it so they could study it in detail. Unfortunately, winter exams and the holidays delayed Löwig's work long enough for another chemist, Antoine-Jérôme Balard, to publish a paper in 1826 describing the new element. Balard was credited with the discovery and named it after the greek word for stench, bromos. Today, bromine is primarily obtained by treating brines from wells in Michigan and Arkansas with chlorine.
From the Greek word bromos, stench. Discovered by Balard in 1826, but not prepared in quantity until 1860.
Pure bromine is a dark red-brown, mobile liquid at ordinary conditions. It gives off a heavy red-brown vapor with a sharp, irritating odor. It freezes to a reddish solid and boils just above room temperature, so noticeable vapor is present from an open container.
Bromine compounds are used in flame retardants for plastics, textiles, and electronic materials, although some older persistent formulations have been restricted or replaced. Dense calcium bromide (CaBr₂), sodium bromide (NaBr), and zinc bromide (ZnBr₂) brines are used in oil and gas drilling and completion fluids. Silver bromide (AgBr) remains important in traditional photographic films and papers. Organobromine intermediates are also used in pharmaceuticals, agrochemicals, dyes, and specialty chemicals.
Elemental bromine is a hazardous material. It causes severe burns when it comes in contact with the skin and its vapor irritates the eyes, nose and throat. Most of the bromine produced in the United States was used in the manufacture of ethylene dibromide(C2H4Br2), a chemical added to leaded gasolines that prevented the accumulation of lead compounds within the engine. With the discontinuation of leaded gasolines in favor of unleaded gasolines, the demand for bromine has been greatly reduced. Silver bromide (AgBr), a chemical used in photography, now accounts for the largest use of bromine. Other bromine compounds are used in fumigants, in flameproofing agents and in some compounds used to purify water. Tyrian purple, an expensive purple dye known to ancient civilizations, was produced from an organic bromine compound secreted from a sea mussel known as the murex.
Bromine is used in making fumigants, flameproofing agents, water purification compounds, dyes, medicines, sanitizers, inorganic bromides for photography, etc. Organic bromides are also important.
Isotopes in Earth/Planetary Science
Molecules, atoms, and ions of the stable isotopes of bromine possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights. There are substantial variations in the isotopic abundances of bromine in natural terrestrial materials (Fig. IUPAC.35.1). These variations are useful in investigating the origin of substances and studying environmental, hydrological, and geological processes [13] M. W. Wieser, T. B. Coplen. Pure Appl Chem.83, 359 (2011)., [278] R. L. Stotler, S. K. Frape, O. Shouakar-Stash. Chem. Geol.274, 38 (2010).. 79Br has been used as a groundwater tracer (Fig. IUPAC.35.2). Introduction of a solution spiked with 79Br to groundwater and measurement of the change in the isotope-amount ratio n(79Br)/n(81Br) over time has been used to monitor tracer breakthrough and to calculate bromide travel time [279] M. D’Alessandro, G. Bidoglio, F. Mousty, J. V. Sala Benito, A. Y. De Llano. J. Hydrol.193, 351 (1997)..
Isotopes in Medicine
77Br (with a half-life of 57 h) is used to label radiopharmaceuticals that bind to estrogen receptors for tumor imaging. 75Br (with a half-life of 97 min) is being used with positron emission tomography (PET) imaging [281] K. D. McElvany, J. A. Katzenellenbogen, K. E. Shafer, B. A. Siegel, S. G. Senderoff, M. J. Welch, Los Alamos Medical Radioisotope Group. J. Nucl. Med.23, 425 (1982)..
Isotopes Used as a Source of Radioactive Isotope(s)
79Br is used in the proton cyclotron to produce 77Kr, which decays to 77Br via the reaction 79Br (p, 3n) 77Kr, which decays into 77Br [282] E. Galiano, R. Tilbury. Appl. Radiat. Isot.49, 105 (1998)..
Bromine commonly forms bromide salts containing Br⁻, including sodium bromide (NaBr) and potassium bromide (KBr). It shows positive oxidation states in interhalogen and oxyanion chemistry, such as bromine chloride (BrCl), hypobromous acid (HOBr), bromate (BrO₃⁻), and perbromate (BrO₄⁻), though the higher oxidation states are less stable than comparable chlorine species. Hydrogen bromide (HBr) is a strong acid in water. Many organobromine compounds are useful synthetic intermediates because carbon-bromine bonds are reactive toward substitution and coupling reactions.
See more information at the Bromine compound page.
Elemental bromine (Br₂) is highly corrosive, toxic by inhalation, and a severe irritant to skin, eyes, and mucous membranes. Its vapor is hazardous even at low concentrations and reacts with many organic materials and reducing agents. Concentrated hydrobromic acid (HBr) is strongly acidic and corrosive. Some organobromine compounds are persistent, bioaccumulative, or toxic, but hazards vary widely with structure and exposure route.
Bromide is a natural constituent of seawater and evaporite brines, and it is cycled through oceans, salt deposits, aerosols, and biological processes. Marine organisms produce many organobromine compounds, some of which enter atmospheric chemistry. In water treatment, bromide can be oxidized to reactive bromine species and brominated disinfection by-products. Persistent brominated flame retardants can accumulate in sediments and biota, depending on their structure and use history.
Commercial bromine is produced mainly by oxidizing bromide-rich brines and stripping the liberated bromine from solution. Major feedstocks include highly saline inland brines, salt-lake brines, and some subsurface brines associated with mineral or hydrocarbon production. Demand is tied to flame retardants, drilling fluids, water-treatment chemicals, and specialty synthesis. Supply is geographically concentrated where suitable brines are available, and recycling is limited for many dispersive uses, although some brominated materials and process streams can be recovered or managed in closed systems.
A member of the halogen group, bromine is obtained from natural brines from wells in Michigan and Arkansas. Some bromine is extracted today from seawater, which contains only about 85 ppm.
Bromine is a relatively scarce element in the cosmos compared with lighter halogens. It is produced by neutron-capture processes in earlier generations of stars and is incorporated into dust, meteorites, and planetary materials in small amounts. On Earth and other volatile-bearing bodies, its geochemistry is controlled mainly by the soluble bromide ion, which concentrates in brines during evaporation.
- Bromine is one of only two elements that are liquid at standard laboratory temperatures; the other is mercury.
- Its name comes from a Greek word referring to stench, reflecting the odor of Br₂ vapor.
- Silver bromide darkens on exposure to light, a property central to photographic emulsions.
- Bromide ions are usually more concentrated in late-stage evaporite brines than in ordinary seawater.
- Elemental bromine is dense enough that many common solids float on it, but contact is dangerous.
Immagini
Proprietà
Fisiche
- Raggio atomico (empirico)
- 115 pm Confronta Raggio atomico (empirico) di tutti gli elementi →
- Raggio covalente
- 120 pm Confronta Raggio covalente di tutti gli elementi →
- Raggio di van der Waals
- 183 pm Confronta Raggio di van der Waals di tutti gli elementi →
- Densità
- 3102,8 kg/m³ Confronta Densità di tutti gli elementi →
- Volume molare
- 0,0235 L/mol
- Fase in condizioni STP
- Liquido Confronta Fase in condizioni STP di tutti gli elementi →
- Punto di fusione
- -7,2 °C Confronta Punto di fusione di tutti gli elementi →
- Punto di ebollizione
- 58,8 °C Confronta Punto di ebollizione di tutti gli elementi →
- Conducibilità termica
- 0,005 W/(m·K) Confronta Conducibilità termica di tutti gli elementi →
- Capacità termica specifica
- 0,474 J/(g·K) Confronta Capacità termica specifica di tutti gli elementi →
- Capacità termica molare
- 75,69 J/(mol·K) Confronta Capacità termica molare di tutti gli elementi →
- Struttura cristallina
- Ortorombica Confronta Struttura cristallina di tutti gli elementi →
Chimiche
- Elettronegatività (Pauling)
- 2,96 Confronta Elettronegatività (Pauling) di tutti gli elementi →
- Elettronegatività (Allen)
- 2,685
- Affinità elettronica
- 3,3635 eV
- Energia di ionizzazione (1ª)
- 11,81381 eV Confronta Energia di ionizzazione (1ª) di tutti gli elementi →
- Energia di ionizzazione (2ª)
- 21,591074 eV Confronta Energia di ionizzazione (2ª) di tutti gli elementi →
- Energia di ionizzazione (3ª)
- 34,87112 eV Confronta Energia di ionizzazione (3ª) di tutti gli elementi →
- Energia di ionizzazione (4ª)
- 47,782164 eV Confronta Energia di ionizzazione (4ª) di tutti gli elementi →
- Energia di ionizzazione (5ª)
- 59,595205 eV Confronta Energia di ionizzazione (5ª) di tutti gli elementi →
- Stati di ossidazione
- −1, +1, +2, +3, +4, +5, +7 Confronta Stati di ossidazione di tutti gli elementi →
- Elettroni di valenza
- 7 Confronta Elettroni di valenza di tutti gli elementi →
- Configurazione elettronica
- [Ar] 4s2 3d10 4p5
Termodinamiche
- Punto triplo (temperatura)
- -7,25 °C
- Punto triplo (pressione)
- 5879 Pa
- Punto critico (temperatura)
- 315 °C
- Punto critico (pressione)
- 1,034e+7 Pa
- Calore di fusione
- 0,10955071 eV Confronta Calore di fusione di tutti gli elementi →
- Calore di vaporizzazione
- 0,31051459 eV Confronta Calore di vaporizzazione di tutti gli elementi →
- Calore di atomizzazione
- 1,159766 eV
- Entalpia di atomizzazione
- 1,159248 eV
Nucleari
- Protoni
- 35 Confronta Protoni di tutti gli elementi →
- Neutroni
- 44 Confronta Neutroni di tutti gli elementi →
- Isotopi noti
- 34 Confronta Isotopi noti di tutti gli elementi →
- Isotopi stabili
- 2 Confronta Isotopi stabili di tutti gli elementi →
- Isotopo più stabile
- Br-79
- Anno della scoperta
- 1825
Abbondanza
- Abbondanza (crosta terrestre)
- 2,4 mg/kg Confronta Abbondanza (crosta terrestre) di tutti gli elementi →
- Abbondanza (oceano)
- 67,3 mg/L Confronta Abbondanza (oceano) di tutti gli elementi →
Struttura cristallina
- Costante reticolare a
- 667 pm
Struttura elettronica
- Elettroni per guscio
- 2, 8, 18, 7 Confronta Elettroni per guscio di tutti gli elementi →
Identificativi
- Numero CAS
- 7726-95-6 Confronta Numero CAS di tutti gli elementi →
- Simbolo di termine
- 2P°3/2
- InChI
- InChI=1S/Br
- Chiave InChI
- WKBOTKDWSSQWDR-UHFFFAOYSA-N
Configurazione elettronica Misurato
Br: 3d¹⁰ 4s² 4p⁵[Ar] 3d¹⁰ 4s² 4p⁵1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁵Modello atomico
Gli isotopi modificano il numero di neutroni, la massa e la stabilità — non la configurazione elettronica di un atomo neutro.
Modello atomico schematico, non in scala.
Impronta atomica
Spettro di emissione / assorbimento
Distribuzione isotopica
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita |
|---|---|---|---|
| 79 Stabile | 78,9183376 ± 0,0000014 | 50,6900% | Stabile |
| 81 Stabile | 80,9162897 ± 0,0000014 | 49,3100% | Stabile |
Fase / Stato
Motivo: tra il punto di fusione (-7,2 °C) e il punto di ebollizione (58,8 °C)
Schema non in scala
Punti di transizione di fase
Energie di transizione
Energia necessaria per fondere 1 mol al punto di fusione
Energia necessaria per vaporizzare 1 mol al punto di ebollizione
Densità
In condizioni standard
Non disponibile per la fase liquida
Avanzate
Spettri atomici
Sono visualizzati 10 di 35. Ordinamento per carica ionica crescente.
Righe disponibili ?
| Ione | Carica | Righe totali | Probabilità di transizione | Designazioni dei livelli |
|---|---|---|---|---|
| Br I | 0 | 170 | 54 | 170 |
| Br II | +1 | 118 | 3 | 0 |
| Br III | +2 | 75 | 0 | 0 |
| Br IV | +3 | 136 | 0 | 136 |
| Br V | +4 | 22 | 0 | 0 |
Livelli disponibili ?
| Ione | Carica | Livelli |
|---|---|---|
| Br I | 0 | 265 |
| Br II | +1 | 132 |
| Br III | +2 | 53 |
| Br IV | +3 | 43 |
| Br V | +4 | 10 |
| Br VI | +5 | 12 |
| Br VII | +6 | 6 |
| Br VIII | +7 | 12 |
| Br IX | +8 | 5 |
| Br X | +9 | 2 |
Raggi ionici
| Carica | Coordinazione | Spin | Raggio |
|---|---|---|---|
| -1 | 6 | N/D | 196 pm |
| +3 | 4 | N/D | 59 pm |
| +5 | 3 | N/D | 31 pm |
| +7 | 4 | N/D | 25 pm |
| +7 | 6 | N/D | 39 pm |
Composti
Isotopi (2)
| Numero di massa | Massa atomica (u) | Abbondanza naturale | Emivita | Modalità di decadimento | |
|---|---|---|---|---|---|
| 79 Stabile | 78,9183376 ± 0,0000014 | 50,6900% ± 0,0700% | Stabile | stable | |
| 81 Stabile | 80,9162897 ± 0,0000014 | 49,3100% ± 0,0700% | Stabile | stable |
Proprietà estese
Raggi covalenti (dati estesi)
- Raggio covalente (Pyykkö)
- 114 pm
- Raggio covalente (Pyykkö, legame doppio)
- 109 pm
- Raggio covalente (Pyykkö, legame triplo)
- 110 pm
- Raggio covalente (Bragg)
- 119 pm
Raggi di van der Waals
- Bondi
- 183 pm
- Batsanov
- 190 pm
- Alvarez
- 186 pm
- UFF
- 418,9 pm
- MM3
- 222 pm
- Dreiding
- 395 pm
- Rowland–Taylor
- 187 pm
Raggi atomici e metallici
- Raggio atomico (Rahm)
- 219 pm
- Raggio metallico (C12)
- 117 pm
Scale di numerazione
- Mendeleev
- 108
- Pettifor
- 98
- Glawe
- 100
Scale di elettronegatività
- Ghosh
- 0
- Gunnarsson–Lundqvist
- 8
- Robles–Bartolotti
- 7
Polarizzabilità e dispersione
- Polarizzabilità dipolare
- 21 a.u.
- Polarizzabilità dipolare (inc.)
- 1 a.u.
- C₆
- 162 Ha·Bohr6
- C₆ (Gould–Bučko)
- 187 Ha·Bohr6
Affinità chimica
- Affinità protonica
- 554,4 kJ/mol
- Basicità in fase gassosa
- 531,2 kJ/mol
Rischio di approvvigionamento ed economia
- Concentrazione della produzione
- 44
- Rischio relativo di approvvigionamento
- 7
- Distribuzione delle riserve
- 64
- Stabilità politica (principale produttore)
- 57
- Stabilità politica (principale detentore di riserve)
- 57
Transizioni di fase e allotropi
| Punto di fusione | 265,95 K |
| Punto di ebollizione | 331,95 K |
| Punto critico (temperatura) | 588,15 K |
| Punto critico (pressione) | 10,34 MPa |
| Punto triplo (temperatura) | 265,9 K |
| Punto triplo (pressione) | 5,88 kPa |
Categorie degli stati di ossidazione
Dati di riferimento avanzati
Costanti di schermaggio (8)
| n | Orbitale | σ |
|---|---|---|
| 1 | s | 0,7529 |
| 2 | p | 3,9436 |
| 2 | s | 9,3566 |
| 3 | d | 15,4409 |
| 3 | p | 15,4292 |
| 3 | s | 14,7815 |
| 4 | p | 25,972 |
| 4 | s | 24,4472 |
Dettaglio dei raggi cristallini (5)
| Carica | CN | Spin | rcrystal (pm) | Origine |
|---|---|---|---|---|
| -1 | VI | 182 | Pauling's (1960) crystal radius, | |
| 3 | IVSQ | 73 | ||
| 5 | IIIPY | 45 | ||
| 7 | IV | 39 | ||
| 7 | VI | 53 | Ahrens (1952) ionic radius, |
Modalità di decadimento degli isotopi (54)
| Isotopo | Modalità | Intensità |
|---|---|---|
| 65 | p | — |
| 66 | p | — |
| 67 | p | — |
| 68 | p | — |
| 69 | p | 100% |
| 70 | B+ | 100% |
| 70 | B+p | — |
| 71 | B+ | 100% |
| 72 | B+ | 100% |
| 73 | B+ | 100% |
Fattori di diffusione dei raggi X (506)
| Energia (eV) | f₁ | f₂ |
|---|---|---|
| 10 | — | 5,16199 |
| 10,1617 | — | 5,31855 |
| 10,3261 | — | 5,47986 |
| 10,4931 | — | 5,64606 |
| 10,6628 | — | 5,8173 |
| 10,8353 | — | 5,99373 |
| 11,0106 | — | 6,17552 |
| 11,1886 | — | 6,36281 |
| 11,3696 | — | 6,5558 |
| 11,5535 | — | 6,75463 |
Dati aggiuntivi
Estimated Crustal Abundance
The estimated element abundance in the earth's crust.
2.4 milligrams per kilogram
Riferimenti (1)
Estimated Oceanic Abundance
The estimated element abundance in the earth's oceans.
6.73×101 milligrams per liter
Riferimenti (1)
Sources
Sources of this element.
A member of the halogen group, bromine is obtained from natural brines from wells in Michigan and Arkansas. Some bromine is extracted today from seawater, which contains only about 85 ppm.
Riferimenti (1)
- [6] Bromine https://periodic.lanl.gov/35.shtml
Production
Production of this element (from raw materials or other compounds containing the element).
Much of the bromine output in the U.S. was used in the production of ethylene dibromide, a lead scavenger used in making gasoline anti-knock compounds. Lead in gasoline, however, has been drastically reduced due to environmental considerations. This will greatly affect future production of bromine.
Riferimenti (1)
- [6] Bromine https://periodic.lanl.gov/35.shtml
Riferimenti
(9)
Data deposited in or computed by PubChem
The half-life and atomic mass data was provided by the Atomic Mass Data Center at the International Atomic Energy Agency.
Element data are cited from the Atomic weights of the elements (an IUPAC Technical Report). The IUPAC periodic table of elements can be found at https://iupac.org/what-we-do/periodic-table-of-elements/. Additional information can be found within IUPAC publication doi:10.1515/pac-2015-0703 Copyright © 2020 International Union of Pure and Applied Chemistry.
The information are cited from Pure Appl. Chem. 2018; 90(12): 1833-2092, https://doi.org/10.1515/pac-2015-0703.
Thomas Jefferson National Accelerator Facility (Jefferson Lab) is one of 17 national laboratories funded by the U.S. Department of Energy. The lab's primary mission is to conduct basic research of the atom's nucleus using the lab's unique particle accelerator, known as the Continuous Electron Beam Accelerator Facility (CEBAF). For more information visit https://www.jlab.org/
The periodic table at the LANL (Los Alamos National Laboratory) contains basic element information together with the history, source, properties, use, handling and more. The provenance data may be found from the link under the source name.
The periodic table contains NIST's critically-evaluated data on atomic properties of the elements. The provenance data that include data for atomic spectroscopy, X-ray and gamma ray, radiation dosimetry, nuclear physics, and condensed matter physics may be found from the link under the source name. Ref: https://www.nist.gov/pml/atomic-spectra-database
This section provides all form of data related to element Bromine.
The element property data was retrieved from publications.