Potassium bromide

Potassium bromide ;
Names:	potassium bromide;
Formula:	KBr;
Molar mass:	119.002 g/mol;
Density:	2.74 g/cm3;
Crystal system:	cubic; a=6.598 Å, b=6.598 Å, c=6.598 Åα=90°, β=90°, γ=90°;
Shapes:	https://en.crystalls.info/w/uploads/media/f/f1/Cube.json Cube https://en.crystalls.info/w/uploads/media/a/af/Tetragonal_prism.json Tetragonal prism https://en.crystalls.info/w/uploads/media/3/30/Tetragonal_flat_prism.json Tetragonal flat prism ;
Color:	colorless;
Melting point:	734 °C1,007.15 K <br />1,353.2 °F <br />1,812.87 °R <br />;
Boiling point:	1380 °C1,653.15 K <br />2,516 °F <br />2,975.67 °R <br />;
Refractive index:	1.559 ;
Magnetic properties:	diamagnetic; χ=-4.91 · 10-5cm³/mol;
Hardness:	strong;
Toxicity:	non-toxic; LD50=3070mg/kg

Description

Inorganic compound, salt of alkaline metal potassium and inorganic hydrobromic acid. Doesn't form water hydrates.

Precursors

Reaction between bromine, potassium hydroxide and hydrogen peroxide

Chemical equation:

2KOH + Br₂ + H₂O₂ = 2KBr + 2H₂O + O₂↑

For preparation of 100.00g of potassium bromide а 47.15g of hydroxide, 476.38g of

3%3%
30%

peroxide and 67.15g of bromine is required.

Add to the flask with hydroxide solution hydrogen peroxide and then add small parts of bromine with stirring until oxide emission will stop. For purifying compound from hydroxide add large amount of cold ethanol, acetone or toluene to solution, salt will settle to the bottom in the form of fine crystals or powder. Filter precipitate and wash it with small amount of the same solvent, then filter the solution and use it for crystal growing.

Reaction between potassium hydroxide or carbonate фтв hydrobromic acid

Chemical equation:

KOH + HBr = KBr + H₂O

K₂CO₃ + 2HBr = 2KBr + H₂O + CO₂↑

For preparation of 100.00g of potassium bromide а 47.15g of hydroxide or 58.07g of carbonate and 141.65g of 48%48% hydrobromic acid is required.

Add acid to the flask, then add small parts of potassium compound with stirring until heating will stop (attention, the solution may boil!) or, if you use carbonate, until carbon dioxide emission will stop.

The problem is that hydrobromic acid is rarely occurs, so reaction is rarely used.

Influence of temperature

Dissolving is endothermic, solution cools much, so use hot water or using heat.

Notes

Often begins to grow as crust at solution surface or vessel walls and it is hard to get rid of it.

Storage conditions

Store in its original form or under several layers of varnish at average humidity and room temperature. Do not store in matchboxes or cotton wool and do not heat.

Solubility

TableGraph

Temperature	гр/`100,00` гр water	гр/`100,00` гр ethanol	гр/`100,00` гр ethanol 50%	гр/`100,00` гр methanol	гр/`100,00` гр acetone	гр/`100,00` гр diethyl ether	гр/`100,00` гр glycerol	гр/`100,00` гр furfural	гр/`100,00` гр ethylene glycol	гр/`100,00` гр formic acid 95%	гр/`100,00` гр propanol	гр/`100,00` гр isopropanol	гр/`100,00` гр isobutanol	гр/`100,00` гр 1-butanol	гр/`100,00` гр 2-butanol	гр/`100,00` гр 1-pentanol	гр/`100,00` гр ammonia	гр/`100,00` гр hydrazine	гр/`100,00` гр ethylenediamine	гр/`100,00` гр hydroxylamine	гр/`100,00` гр acetonitrile	гр/`100,00` гр isoamyl alcohol
0°C273.15 K <br />32 °F <br />491.67 °R <br />	`53.85`			`1.82`													`26.87`
10°C283.15 K <br />50 °F <br />509.67 °R <br />	`59.49`
15°C288.15 K <br />59 °F <br />518.67 °R <br />						`0.02`
20°C293.15 K <br />68 °F <br />527.67 °R <br />	`65.02`		`16.4`	`2.08`	`0.00359`					`23.2`				`0.0112`	`0.0044`			`60`		`44.7`	`0.0023`	`0.002`
25°C298.15 K <br />77 °F <br />536.67 °R <br />	`67.79`	`0.135`		`2.17`			`17.8`	`0.12`			`0.0035`	`0.0011`	`0.0076`			`0.003`	`13.5`		`0.78`			`0.00175`
30°C303.15 K <br />86 °F <br />545.67 °R <br />	`70.65`								`15.85`
40°C313.15 K <br />104 °F <br />563.67 °R <br />	`76.06`			`2.37`
50°C323.15 K <br />122 °F <br />581.67 °R <br />	`81.16`
60°C333.15 K <br />140 °F <br />599.67 °R <br />	`85.87`
70°C343.15 K <br />158 °F <br />617.67 °R <br />	`90.84`
80°C353.15 K <br />176 °F <br />635.67 °R <br />	`95.31`
90°C363.15 K <br />194 °F <br />653.67 °R <br />	`99.2`
100°C373.15 K <br />212 °F <br />671.67 °R <br />	`103.25`

Slightly soluble in pyridine.

Gallery

Sources

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Bromides
Salts	Potassium bromide (KBr) • Sodium bromide (NaBr)
Adducts	Glucose and sodium bromide complex (2C₆H₁₂O₆ · NaBr)

Potassium compounds
Salts	Potassium bromate (KBrO₃) • Potassium bromide (KBr) • Potassium chlorate (KClO₃) • Potassium chloride (KCl) • Potassium chromate (K₂CrO₄) • Potassium dihydrophosphate (KH₂PO₄) • Potassium dichromate (K₂Cr₂O₇) • Potassium iodide (KI) • Potassium hydrofluoride (KHF₂) • Potassium hydrophosphate (K₂HPO₄) • Potassium hydrophthalate (KC₈H₆O₄) • Potassium metavanadate (KVO₃) • Potassium nitrate (KNO₃) • Potassium sulfate (K₂SO₄) • Potassium thiocyanate (KNCS)
Double salts	Aluminum-potassium sulfate (KAl(SO₄)₂) • Antimony(III)-potassium tartrate (K₂Sb₂(C₄H₂O₆)₂) • Chromium(III)-potassium sulfate (KCr(SO₄)₂) • Cobalt(II)-potassium sulfate (K₂Co(SO₄)₂) • Copper(II)-potassium sulfate (K₂Cu(SO₄)₂) • Indium(III)-potassium sulfate (KIn(SO₄)₂) • Iron(II)-potassium sulfate (K₂Fe(SO₄)₂) • Iron(III)-potassium sulfate (KFe(SO₄)₂) • Lithium-potassium sulfate (KLiSO₄) • Magnesium-potassium sulfate (K₂Mg(SO₄)₂) • Magnesium-potassium sulfate-chromate (K₂CrO₄ · MgSO₄) • Manganese(II)-potassium sulfate (K₂Mn(SO₄)₂) • Nickel-potassium sulfate (K₂Ni(SO₄)₂) • Potassium-sodium tartrate (KNaC₄H₄O₆) • Vanadium(III)-ammonium sulfate (NH₄V(SO₄)₂)
Complexes	Potassium dioxalatocuprate(II) (K₂[Cu(C₂O₄)₂]) • Potassium hexanitrocobaltate(III) (K₃[Co(NO₂)₆]) • Potassium hexachlororhodiate(III) (K₃[RhCl₆]) • Potassium hexacyanocobaltate(III) (K₃[Co(CN)₆]) • Potassium hexacyanoferrate(II) (K₄[Fe(CN)₆]) • Tripotassium-sodium hexacyanoferrate(II) (K₃Na[Fe(CN)₆]) • Potassium hexacyanoferrate(III) (K₃[Fe(CN)₆]) • Potassium hexacyanochromate(III) (K₃[Co(CN)₆]) • Potassium tetraiodobismuthate (К[BiI₄]) • Potassium tetraiodomercurate(II) (K₂[HgI₄]) • Potassium trioxalatoaluminate (K₃[Al(C₂O₄)₃]) • Potassium trioxalatocobaltate(III) (K₃[Co(C₂O₄)₃]) Potassium trioxalatoferrate(III) (K₃[Fe(C₂O₄)₃]) • Potassium-sodium trioxalatoferrate(III) (K₅Na[Fe(C₂O₄)₃]₂) • Dipotassium-sodium trioxalatoferrate(III) (K₂Na[Fe(C₂O₄)₃]) • Potassium trioxalatochromate(III) (K₃[Cr(C₂O₄)₃])

Potassium bromide
Names:	potassium bromide
Formula:	KBr
Molar mass:	119.002 g/mol
Density:	2.74 g/cm³
Crystal system:	cubic a=6.598 Å, b=6.598 Å, c=6.598 Åα=90°, β=90°, γ=90°
Shapes:	Cube Tetragonal prism Tetragonal flat prism
Color:	colorless
Melting point:	734 °C1,007.15 K <br />1,353.2 °F <br />1,812.87 °R <br />
Boiling point:	1380 °C1,653.15 K <br />2,516 °F <br />2,975.67 °R <br />
Refractive index:	1.559
Magnetic properties:	diamagnetic χ=-4.91 · 10^-5cm³/mol
Hardness:	strong
Toxicity:	non-toxic LD₅₀=3070mg/kg