Page 204 - Academic Press Encyclopedia of Physical Science and Technology 3rd Analytical Chemistry

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Encyclopedia of Physical Science and Technology EN007C-340 July 10, 2001 14:45

Infrared Spectroscopy 815

TABLE IV (continued )
Group a Wave number region (cm −1 b Assignment c
)
C CH 2 CH 2 CI (gauche) 649–635 m C CI str.
CH 2 CI 1300–1240 m CH 2 wag
Sulfur
SH 2590–2540 w SH str.
CH 2 S 1270–1220 m CH 2 wag
SO 2 1400–1300 s SO 2 out-of-phase str.
SO 2 1200–1100 s SO 2 in-phase str.
SO 3 Na 1230–1120 s SO 3 out-of-phase str.
SO 3 Na 1080–1025 m SO 3 in-phase str.
Phosphorus
PH 2440–2275 m PH str.
P O 1320–1140 s P O str.
P O C 1050–970 s P O C str.
Silicon
SiH 2250–2100 s SiH str.
Si CH 3 1280–1255 s CH 3 in-phase def.
Si O R 1110–1000 s Si O C str.
Si O Si 1110–1000 s Si O Si str.
Boron
BH 2640–2350 s BH str.
B ··· H ··· B 2220–1540 ms BH str.
B O 1380–1310 s BO str.
a R is an alkane group.
b Wave number regions given in cm −1 . Relative intensities are indicated by s (strong), m (medium), w
(weak), and v (variable).
c Abbreviations: str., stretch; def., deformation; sym., symmetric; antisym., antisymmetric.
d CH 2 rock is CH 2 rotation in the CH 2 plane.
e
Wag is rotation out of the CH 2 plane or out of the aryl or olefinic plane.
f
Fermi resonance doublet, CH stretch + CH deformation overtone.
in alcohols and phenols and water have bands. Various olefins. In aromatics, these bands can usually distinguish
types of NH also absorb here, as well as acetylenic CH the number of adjacent aromatic hydrogens between sub-
−1
groups. In the region from 3100 to 3000 cm , absorption stituents: five for monosubstituted, four for ortho, three
occurs for aryl CH and olefinic CH. In the region from and one for meta, and two for para.
−1
3000 to 2800 cm , various types of CH 3 and CH 2 groups In the range from 1400 to 900 cm −1 vibrations from
absorb. Strongly hydrogen bonded hydrogens in acidic SO 2 , SO 3 ,P O, and many types of C O groups have
compounds absorb broadly in the region from 3100 to strong bands. Usually below 1350 cm −1 only strong bands
−1
2400 cm . Finally, SH, BH, PH, and SiH groups absorb are interpreted since there are many bands in this region
−1
in the region from 2600 to 2100 cm . that are not group frequencies. This, of course, is only a
Various types of triple bonds such as nitriles and cumu- very small sample of the large body of group frequency
lated double bonds such as isocyanate groups absorb in the correlations available for qualitative analysis that can be
−1
region from 2300 to 1900 cm . Various types of double found in IR texts.
bonds, including C O, C N, and C C absorb from 1900
−1
to 1550 cm . Aromatic ring vibrations absorb near 1600
−1
and 1500 cm .
Hydrogen bending vibrations absorb from 1600 to SEE ALSO THE FOLLOWING ARTICLES
−1
700 cm . Bending vibrations for CH 2 and CH 3 absorb
−1
from 1500 to 1350 cm , and very useful out-of-plane CH INFRARED ASTRONOMY • INFRARED TECHNOLOGY •
wag vibrations in olefins and aromatics absorb from 1000 MACROMOLECULES,STRUCTURE • MICROWAVE MOLEC-
−1
to 700 cm .Inolefins these can be used to distinguish ULAR SPECTROSCOPY • RADIOMETRY AND PHOTOMETRY
vinyls, vinylidines, and cis and trans 1,2-disubstituted • RAMAN SPECTROSCOPY