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why KBr is used in FTIR SPECTROSCOPY and why is it necessary
to triturate KBr during FTIR analysis?
- 25 Answers
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Answer / sudhanshu raghuvanshi
KBr is an alkyl halide and any alkyl halide doe not show
any absorption spectrum in infrared region.......we can
also use kcl....for the ir of liquid we use nacl cells
because it is also an alkyl halide and does not show any
absorption spectrum in IR region.......
| Is This Answer Correct ? | 136 Yes | 46 No |
Answer / surya prakash
kbr is one of the compounds which donot absorb the provided
radiations of "IR" and hence donot exhibit its absorption
pattern in the graph.........&&&&&&&
:
:
kbr only to make sure that the sample stands correctly and
its uniformly distributed in the pellet
| Is This Answer Correct ? | 60 Yes | 19 No |
Answer / p.srikanth 8099229714
KBr does not
absorb infrared
radiation in the
reagion 4000-650
cm inverce.
For more data
spectroscorpy of
organic compounds
by p.s.kalsi (page
no 85)
| Is This Answer Correct ? | 39 Yes | 9 No |
Answer / veerasekhar
KBr Does not react with that of our Sample which is to be
analysed
| Is This Answer Correct ? | 50 Yes | 26 No |
Answer / krishnam raju
kbr is one of the compounds which donot absorb the provided
radiations of "IR" and hence donot exhibit its absorption
when we applying pressure during pellet making KBr melts
to pellet form whereas other salts are not melts
| Is This Answer Correct ? | 33 Yes | 9 No |
Answer / nishabd
KBr is inert it doesnt react with the sample to be analysed...it helps in better resolution of the peaks as it doesnt show absorbance in the IRregion..it is highly stable, so the background scanned once can be used for a longer duration of analysis(i.e:until many containers of a batch for example)
| Is This Answer Correct ? | 30 Yes | 7 No |
Answer / amruta
1) Small amount of sample is used.
2) KBr pellets produces excellent spectra.
3) It transmits most of the IR region
| Is This Answer Correct ? | 63 Yes | 41 No |
Answer / bem nyax
This method exploits the property that alkali halides become plastic when subjected to pressure and form a sheet that is transparent in the infrared region. Potassium bromide (KBr) is the commonest alkali halide used in the pellets. Cesium iodide (CsI) may also be used to measure the infrared spectrum in the 400 to 250 cm-1 low-wavenumber region.
The preparation method for 13 mm-diameter pellets is described below. Approximately 0.1 to 1.0 % sample is well mixed into 200 to 250 mg fine alkali halide (the example of KBr is used below) powder and then finely pulverized and put into a pellet-forming die. A force of approximately 8 tons is applied under a vacuum of several mm Hg for several minutes form transparent pellets. Degassing is performed to eliminate air and moisture from the KBr powder. Inadequate vacuum may result in easily broken pellets that scatter light. Before forming the KBr powder into pellets, pulverize it to 200 mesh max. and then dry at approximately 110 °C for two to three hours. Note that rapid heating can oxidize some of the KBr powder to KBrO3, causing a brown discoloration. After drying the powder, store it in a desiccator.
When performing measurements, the background can be measured with an empty pellet holder inserted into the sample chamber. However, background measurements on a pellet holder with a pellet of KBr only, that contains no sample, can correct for infrared light scattering losses in the pellet and for moisture adsorbed on the KBr.
Reference >> http://www.shimadzu.com/an/ftir/support/ftirtalk/talk8/intro.html
| Is This Answer Correct ? | 14 Yes | 0 No |
Answer / aditya
I Think KBr is an ionic Compound It Has Polarity[k+ and Br-
(KBr)] butnot Dipolmoment so there is no chance to
Vibrational Strectching or bending Hence if we use KBr in
Predict the IR Spectra of our product(should be Covalent
bonded) it gives good Spectra
| Is This Answer Correct ? | 17 Yes | 4 No |
Answer / nishabd
trituration of KBr is followed to avoid light scattering due to large size of the KBr crystals..
| Is This Answer Correct ? | 12 Yes | 7 No |
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