Silver bromide

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Crystal structure
Structure of silver bromide
__ Ag +      __ Br -
Crystal system


Space group

Fm 3 m (No. 225)Template: room group / 225

Coordination numbers

Ag [6], Br [6]

Surname Silver bromide
Ratio formula AgBr
Brief description

white to yellowish green solid

External identifiers / databases
CAS number 7785-23-1
EC number 232-076-8
ECHA InfoCard 100.029.160
PubChem 66199
ChemSpider 59584
Wikidata Q407515
Molar mass 187.77 g mol −1
Physical state



6.47 g cm −3

Melting point

430 ° C

boiling point

1502 ° C


almost insoluble in water, 0.14 mg l −1 (25 ° C)

safety instructions
GHS labeling of hazardous substances
09 - Dangerous for the environment


H and P phrases H: 410
P: 273-391-501
Thermodynamic properties
ΔH f 0

−100.4 kJ / mol

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Silver bromide is a chemical compound of silver that is one of the bromides . It is a widely used chemical in photochemistry that breaks down when exposed to light.


Silver bromide occurs naturally in the form of the mineral bromogyrite .

Extraction and presentation

Silver bromide precipitates out as a yellowish-whitish precipitate when silver salt, usually silver nitrate, and a soluble bromine salt meet.

The compound can also be obtained by reacting silver with bromine under excess pressure at 500 ° C.


Silver bromide

Dry freshly extracted silver bromide looks yellowish. Its melt is orange-red. It is very difficult in water, difficult in concentrated ammonia solution and easily soluble in thiosulphate and cyanide solution. It quickly turns dark in the light as a result of silver deposition through photolytic decomposition . Silver bromide has a cubic crystal structure of the sodium chloride type.


Main article: Photography

The salt is stored in small crystal fragments in a gelatin layer (or similar substances). When light falls on this, the silver bromide decomposes into its elementary components - silver and bromine ; the bromine evaporates. The exposed crystals stand out from the background because the finely divided silver appears black.

Individual evidence

  1. Entry on silver bromide. In: Römpp Online . Georg Thieme Verlag, accessed on November 12, 2014.
  2. a b c d e Entry on silver bromide in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
  3. David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Inorganic Compounds, pp. 4-88.
  4. David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-4.
  5. C. Doelter, H. Leitmeier: Haloid salts, fluorides, organic compounds (coal, asphalt, petroleum), supplements, general register (final volume) . Springer-Verlag, 2013, ISBN 978-3-642-49884-8 , pp. 72 ( limited preview in Google Book search).
  6. ^ A b c Egon Wiberg: Inorganic Chemistry . Walter de Gruyter, 1952, ISBN 978-3-11-143954-9 , pp. 442 ( limited preview in Google Book search).
  7. a b c Rudolf Keim: Silver Part B 2. Compounds with bromine, iodine and astatine . Springer-Verlag, 2013, ISBN 978-3-662-13330-9 , pp. 94 ( limited preview in Google Book search).
  8. RW BERRIMAN, RH HERZ: Twinning and the Tabular Growth of Silver Bromide Crystals. In: Nature. 180, 1957, p. 293, doi : 10.1038 / 180293a0 .