Potassium bromide

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  Potassium bromide   
Names:
Formula: KBr
SMILES: [K+].[Br-]
Molar mass: 119.002 g/mol
Density: 2.74 g/cm3
Crystal system: cubic
a=6.598 Å
6.5980 Å
0.6598 nm
, b=6.598 Å
6.5980 Å
0.6598 nm
, c=6.598 Å
6.5980 Å
0.6598 nm
α=90°
90°  
, β=90°
90°  
, γ=90°
90°  

Shapes:
https://media.crystalls.info/w/uploads/media/Cube.json
https://media.crystalls.info/w/uploads/media/Tetragonal_prism.json
https://media.crystalls.info/w/uploads/media/Tetragonal_flat_prism.json

Color: colorless
Melting point: 734 °C
1,007.15 K
1,353.2 °F
1,812.87 °R

Boiling point: 1380 °C
1,653.15 K
2,516 °F
2,975.67 °R

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% 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% 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

Temperatureгр/100,00 гр waterгр/100,00 гр ethanolгр/100,00 гр ethanol 50%гр/100,00 гр methanolгр/100,00 гр acetoneгр/100,00 гр diethyl etherгр/100,00 гр glycerolгр/100,00 гр furfuralгр/100,00 гр ethylene glycolгр/100,00 гр formic acid 95%гр/100,00 гр propanolгр/100,00 гр isopropanolгр/100,00 гр isobutanolгр/100,00 гр 1-butanolгр/100,00 гр 2-butanolгр/100,00 гр 1-pentanolгр/100,00 гр ammoniaгр/100,00 гр hydrazineгр/100,00 гр ethylenediamineгр/100,00 гр hydroxylamineгр/100,00 гр acetonitrileгр/100,00 гр isoamyl alcohol
0°C
273.15 K
32 °F
491.67 °R
53.85
53.85 g/100g
35.002 %
1.82
1.82 g/100g
1.787 %
26.87
26.87 g/100g
21.179 %
10°C
283.15 K
50 °F
509.67 °R
59.49
59.49 g/100g
37.3 %
~1.95
1.95 g/100g
1.913 %
15°C
288.15 K
59 °F
518.67 °R
~62.3
62.3 g/100g
38.386 %
~2.02
2.02 g/100g
1.98 %
0.02
0.02 g/100g
0.02 %
20°C
293.15 K
68 °F
527.67 °R
65.02
65.02 g/100g
39.401 %
16.4
16.4 g/100g
14.089 %
2.08
2.08 g/100g
2.038 %
0.00359
0.00359 g/100g
0.00359 %
23.2
23.2 g/100g
18.831 %
0.0112
0.0112 g/100g
0.0112 %
0.0044
0.0044 g/100g
0.0044 %
60
60 g/100g
37.5 %
44.7
44.7 g/100g
30.891 %
0.0023
0.0023 g/100g
0.0023 %
0.002
0.002 g/100g
0.002 %
25°C
298.15 K
77 °F
536.67 °R
67.79
67.79 g/100g
40.402 %
0.135
0.135 g/100g
0.135 %
2.17
2.17 g/100g
2.124 %
17.8
17.8 g/100g
15.11 %
0.12
0.12 g/100g
0.12 %
0.0035
0.0035 g/100g
0.0035 %
0.0011
0.0011 g/100g
0.0011 %
0.0076
0.0076 g/100g
0.0076 %
0.003
0.003 g/100g
0.003 %
13.5
13.5 g/100g
11.894 %
0.78
0.78 g/100g
0.774 %
0.00175
0.00175 g/100g
0.00175 %
30°C
303.15 K
86 °F
545.67 °R
70.65
70.65 g/100g
41.401 %
~2.24
2.24 g/100g
2.191 %
15.85
15.85 g/100g
13.681 %
40°C
313.15 K
104 °F
563.67 °R
76.06
76.06 g/100g
43.201 %
2.37
2.37 g/100g
2.315 %
50°C
323.15 K
122 °F
581.67 °R
81.16
81.16 g/100g
44.8 %
60°C
333.15 K
140 °F
599.67 °R
85.87
85.87 g/100g
46.199 %
70°C
343.15 K
158 °F
617.67 °R
90.84
90.84 g/100g
47.6 %
80°C
353.15 K
176 °F
635.67 °R
95.31
95.31 g/100g
48.799 %
90°C
363.15 K
194 °F
653.67 °R
99.2
99.2 g/100g
49.799 %
100°C
373.15 K
212 °F
671.67 °R
103.25
103.25 g/100g
50.8 %
Slightly soluble in pyridine.

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