Potassium Bromide
Chemical Properties
|
KBr |
|
Identifiers |
|
CAS number |
[7758-02-3] |
|
PubChem |
253877 |
|
RTECS number |
TS7650000 |
|
Properties |
|
Molecular formula |
KBr |
|
Molar mass |
119.002 g/mol |
|
Appearance |
white solid |
|
Density |
2.75 g/cm3 |
|
Melting point |
734 °C, 1007 K, 1353 °F |
|
Boiling point |
1435 °C, 1708 K, 2615 °F |
|
Solubility in water |
53.5 g/100 ml (0 °C)
102 g/100 mL (100 °C) |
|
Solubility in glycerol |
21.7 g/100 mL |
|
Solubility in ethanol |
4.76 g/100 mL (80 °C) |
|
Structure |
|
Crystal structure |
Sodium chloride |
|
Coordination
geometry |
octahedral |
|
Dipole moment |
10.41 D (gas) |
|
Hazards |
|
EU Index |
Not listed |
|
Related compounds |
|
Other anions |
Potassium fluoride
Potassium chloride
Potassium iodide |
|
Other cations |
Lithium bromide
Sodium bromide
Rubidium bromide
Caesium bromide |
It is a typical ionic salt which
is fully dissociated and near pH 7 in aqueous solution. It serves as a source of bromide ions- this reaction is important
for the manufacture of silver bromide for photographic film:
-
KBr(aq) + AgNO3(aq) → AgBr(s) +
KNO3(aq)
Aqueous bromide Br- will also form
complexes when reacted with some metal halides such as copper(II)
bromide:
-
2 KBr(aq) + CuBr2(aq) → K2[CuBr4](aq)
It is used extensively in
photography. It is also sometimes used as a bromide
source in organic synthesis, since it is less
hygroscopic than sodium bromide. In the laboratory KBr is
commonly used in infrared spectroscopy. The sample to be
tested is crushed up with a large excess of KBr and
then the mixture is crushed to form a tablet which is
inserted into the spectrophotometer.
Preparation:A traditional method for the
manufacture of KBr is the reaction of
potassium carbonate with a bromide of
iron, Fe3Br8, made
by treating scrap iron under water with
excess bromine:
-
4 K2CO3 +
Fe3Br8 → 8 KBr
+ Fe3O4 + 4 CO2
Medical and
VeterinaryThe
anticonvulsant
properties of
KBr
were first noted by
Sir Charles Locock
at a meeting of the
Royal Medical and
Chirurgical Society
in 1857. Bromide can
be regarded as the
first effective
medication for
epilepsy. At the
time, it was
commonly thought
that epilepsy was
caused by
masturbation. Locock
noted that bromide
calmed sexual
excitement and
thought this was
responsible for his
success in treating
seizures. There
would not be a
better drug for
epilepsy until
phenobarbital in
1912. It was often
said the British
Army laced the
soldiers' tea with
bromide to quell
sexual arousal,
however because
doing so would also
diminish alertness
in battle it is
likely to be an
urban legend and
similar stories were
also told about a
number of
substances.
Potassium bromide
is used to treat
epilepsy in dogs,
either as first-line
treatment or in
addition to phenobarbital when
the seizures are not
adequately
controlled with
phenobarbital alone.
Use of bromide in
cats is limited
because it carries a
substantial risk of
causing lung
inflammation (pneumonitis)
in this species.
KBr
is not approved by
the US Food and Drug
Administration (FDA)
for use in humans to
control seizures. In
Germany KBr continues
to be approved for
use as an
antiepileptic drug
for humans,
particularly
children and
adolescents. These
indications include
severe forms of
generalized tonic-clonic
seizures,
early-childhood-related
Grand-Mal-seizures,
and also severe
myoclonic seizures
during childhood.
Adults who have
reacted positively
to the drug during
childhood/adolescence
may continue
treatment. KBr is
sold under the brand
name Dibro-Be mono
(RX-only). When used
for proper
indications it shows
promising results.
The drug has almost
complete
bioavailability and
an extremely long
half-life of 6
weeks. One tablet
contains 850 mg of
potassium bromide.
It is
not known to
interfere with the
absorption or
excretion of any
other
anticonvulsant.
The therapeutic
index is very small
for bromide. As with
other antiepileptics,
sometimes even
therapeutic doses
give rise to
intoxication. Often
indistinguishable
from 'expected'
side-effects, these
include:
Loss of
appetite,
nausea/emesis,
lethargy,
propensity to
sleep during the
daytime,
depression, loss
of concentration
and memory,
confusion,
headache, and
Bromism
(central
reactions
reaching from
somnolence to
coma, cachexia,
exicosis, loss
of reflexes or
pathologic
reflexes, clonic
seizures,
tremor, ataxia,
loss of neural
sensitivity,
paresis,
papillar edema
of the eyes,
abnormal speech,
cerebral edema,
delirium,
aggressiveness,
psychoses), Acne-form
dermatitis and
other forms of
skin disease may
also be seen, as
well as mucous
hypersecretion
in the lungs.
Asthma and
rhinitis may
worsen. Rarely,
tongue disorder,
aphten, bad
breath, and
obstipation
occur.
OpticsKBr is
transparent from the
near ultraviolet to
long wave infrared
wavelengths (0.25-25
µm). It has no
significant optical
absorption lines in
its high
transmission region.
It is used for
optical windows and
prisms. It must be
kept in a dry
environment due to
high solubility and
hygroscopic nature.
The refractive index
is about 1.55 at 1.0
µm.
In infrared
spectroscopy,
samples are analyzed
by grinding with KBr
powder, and pressing
into a disc.
Alternatively, the
samples may be
analyzed as a liquid
film (neat, as a
solution, or in a
mull with Nujol)
between two polished
KBr discs.
Potassium Bromide manufacturers at:
MUBY CHEMICALS
S-8, SARIFA MANSION, 2ND FLANK ROAD, CHINCHBUNDER, MUMBAI
400009, INDIA.
TEL: (OFFICE) 91-22-23770100, 23726950, 23774610,
23723564. FAX: 91-22-23728264.
e-mail:
info@mubychem.com
Cell Call
to Anmol: +91-9821870100
USA & Canadian Customers may Call
773-829-5811
Copyright
and Usual
Disclaimer
is Applicable.
Last
updated: 10 December, 2011.
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--------
--------
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your work to be done well, then go to a busy man.
The other one
has no time.
