ABSTRACT
Approximate Frequency
Wavelength
Compound or Group
Origin
3700 cm−1
2.70 μ
H2O
Water in solvent
3650
2.74
H2O
Water in some quartz windows
3450
2.9
H2O
H-bonded water. Sometimes found in KBr disks
2350
4.26
CO2
Atmospheric absorption
2330
4.3
CO2
Dissolved gas from dry ice
2300 and 2150
4.35 and 4.65
CS2
Leaky cells
1996
5.01
BO2
Metaborate in the halide window
1400–2000
5–7
H2O
Atmospheric absorption
1820
5.52
COCl2
Decomposition product in purified HCCl3
1755
5.7
Phthalic anhydride
Decomposition product of phthalate esters or resins
1700–1760
5.7–5.9
C=0
Bottle-cap liners leached by sample
1720
5.8
Phthalates
From plastic tubing
1640
6.1
H2O
Entrained in sample, or water of crystallization
1520–1620
6.2–6.6
https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203742433/53e9912e-dfc3-42b1-91b1-4eaf447a0f76/content/ufig35_1.tif"/>
Reaction product of alkali halide windows or KBr pellet with organic acid
1520
6.6
CS2
Leaky cells
1430
7.0
CO3 −2
Contaminant in halide window
1360
7.38
NO3 -
Contaminant in halide window
1270
7.9
SiCH3
Silicone oil or grease
1110
9.0
?
Impurity in KBr for disks
1000–1110
9–10
SiOSi
Glass; silicones
980
10.2
K2SO4
From double decomposition of sulfates in KBr pellets
935
10.7
(CH2O)x
Deposit from gaseous formaldehyde
907
11.02
CCl2 F2
Dissolved Freon 12
837
11.95
NaNO3
(See 7.38 μ)
823
12.15
KNO3
From double decomposition of nitrates in KBr pellets
794
12.6
CCl4 vapor
Leaky cells
788
12.7
CCl4 liquid
Incomplete drying of cell or contamination
520720 and 730
13.7 and 13.9
Polyethylene
728
13.75
Na2SiF6
SiF4 + NaCl windows
667
14.98
CO2
Atmosphere (beam imbalance)
Any
Fringes
If refractive index difference between sample and windows high, or if a cell is partially empty, interference fringes may appear.
REFERENCE: Launer, P. C., Perkin-Elmer Instrument News. 13(3), 10,1962.