{{chembox | Watchedfields = changed | verifiedrevid = 443321289 | ImageFile = CsCl polyhedra.png | ImageSize = | ImageFile1 = Caesium-bromide-3D-ionic.png | IUPACName = Cesium bromide | OtherNames = Cesium bromide,<br/>Caesium(I) bromide |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 22994 | SMILES = [Cs+].[Br-] | InChIKey = LYQFWZFBNBDLEO-REWHXWOFAA | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/BrH.Cs/h1H;/q;+1/p-1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = LYQFWZFBNBDLEO-UHFFFAOYSA-M | CASNo = 7787-69-1 | CASNo_Ref = {{cascite|correct|CAS}} | EINECS = 232-130-0 | RTECS = FK9275000 | UNII = 06M25EDM3F | PubChem = 24592 | InChI = 1/BrH.Cs/h1H;/q;+1/p-1 }} |Section2={{Chembox Properties | Formula = CsBr | MolarMass = 212.809 g/mol<ref name=r1>Haynes, p. 4.57</ref> | Appearance = White solid | Density = 4.43 g/cm<sup>3</sup><ref name=r1/> | MeltingPtC = 636 | MeltingPt_ref = <ref name=r1/> | BoilingPtC = 1300 | BoilingPt_ref = <ref name=r1/> | Solubility = 1230 g/L (25 °C)<ref name=r1/> Disputed. 420 g/L (11 °C) See References<br/> 560 /L (15°C)<br/>1020 g/L (28.5 °C)<br/>1180 g/L (31 °C)<br/>1240 g/L (32.5 °C)<br/>1380 g/L (35 °C) | RefractIndex = 1.8047 (0.3 μm)<br/>1.6974 (0.59 μm)<br/>1.6861 (0.75 μm)<br/>1.6784 (1 μm)<br/>1.6678 (5 μm)<br/>1.6439 (20 μm)<ref>Haynes, p. 10.240</ref> | MagSus = −67.2·10<sup>−6</sup> cm<sup>3</sup>/mol<ref>Haynes, p. 4.132</ref> }} |Section3={{Chembox Structure | CrystalStruct = CsCl, cP2 | SpaceGroup = Pm{{overline|3}}m, No. 221<ref name=str2>{{cite journal|doi=10.1063/1.1713597|title=Elastic Constants of CsBr and CsI from 4.2K to Room Temperature|journal=Journal of Applied Physics|volume=35|issue=4|pages=1222|year=1964|last1=Vallin|first1=J.|last2=Beckman|first2=O.|last3=Salama|first3=K.|bibcode=1964JAP....35.1222V}}</ref> | LattConst_a = 0.4291 nm | UnitCellFormulas = 1 | UnitCellVolume =0.0790 nm<sup>3</sup> | Coordination = Cubic (Cs<sup>+</sup>)<br/>Cubic (Br<sup>−</sup>) }} |Section4={{Chembox Hazards | NFPA-H = 2 | NFPA-F = 0 | NFPA-R = 0 | GHSSignalWord=Warning | GHSPictograms={{GHS07}} | HPhrases = {{H-phrases|302|315|319|335}} | PPhrases = {{P-phrases|261|264|270|271|280|301+312|302+352|304+340|305+351+338|312|321|330|332+313|337+313|362|403+233|405|501}} | FlashPt = Non-flammable | LD50 = 1400 mg/kg (oral, rat)<ref>[https://pubchem.ncbi.nlm.nih.gov/#tab/sidsrcname=ChemIDplus&query=7787-69-1&input_type=text Caesium bromide]. nlm.nih.gov</ref> }} |Section8={{Chembox Related | OtherAnions = Caesium fluoride<br/>Caesium chloride<br/>Caesium iodide<br/>Caesium astatide | OtherCations = Sodium bromide<br/>Potassium bromide<br/>Rubidium bromide<br/>Francium bromide }} }}

'''Caesium bromide''' or '''cesium bromide''' is an ionic compound of caesium and bromine with the chemical formula CsBr. It is a white or transparent solid with melting point at 636&nbsp;°C that readily dissolves in water. Its bulk crystals have the cubic CsCl structure, but the structure changes to the rocksalt type in nanometer-thin film grown on mica, LiF, KBr or NaCl substrates.<ref name=str>{{cite journal|doi=10.1107/S0365110X51001641|title=Polymorphism of cesium and thallium halides|journal=Acta Crystallographica|volume=4|issue=6|pages=487–489|year=1951|last1=Schulz|first1=L. G.|bibcode=1951AcCry...4..487S }}</ref>

== Synthesis == Caesium bromide can be prepared via neutralization reactions: : CsOH + HBr → CsBr + H<sub>2</sub>O : Cs<sub>2</sub>(CO<sub>3</sub>) + 2 HBr → 2 CsBr + H<sub>2</sub>O + CO<sub>2</sub> It can also be prepared by direct synthesis: : 2 Cs + Br<sub>2</sub> → 2 CsBr The direct synthesis is a vigorous reaction of caesium with bromine. Due to its high cost, it is not used for preparation.

== Uses == Caesium bromide is sometimes used in optics as a beamsplitter component in wide-band spectrophotometers.{{Citation needed|date=January 2026}}

==References== {{Reflist}}

==Cited sources== *{{RubberBible92nd}} * [http://www.crystran.co.uk/caesium-bromide-csbr.htm Crystran Ltd experimental data July 2021] {{Webarchive|url=https://web.archive.org/web/20121218002818/http://www.crystran.co.uk/caesium-bromide-csbr.htm |date=2012-12-18 }}

== External links == {{Commons category|Caesium bromide}} * [http://physchem.ox.ac.uk/MSDS/CA/caesium_bromide.html MSDS at Oxford University] {{Webarchive|url=https://web.archive.org/web/20071017044744/http://physchem.ox.ac.uk/MSDS/CA/caesium_bromide.html |date=2007-10-17 }} * [http://www.crystran.co.uk/caesium-bromide-csbr.htm Crystran Physical data] {{Webarchive|url=https://web.archive.org/web/20121218002818/http://www.crystran.co.uk/caesium-bromide-csbr.htm |date=2012-12-18 }}, [https://web.archive.org/web/20070927230133/http://www.korth.de/transmiss/csbr.htm IR transmission spectrum] * [http://doc.cern.ch/tmp/convert_SCAN-9806049.pdf Ultra-violet photoabsorption measurements in alkali iodide and caesium bromide evaporated films]

{{Caesium compounds}} {{Bromides}} {{Authority control}}

Category:Caesium compounds Category:Alkali metal bromides Category:Caesium chloride crystal structure