N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
360
7 IR
7.11.6 Acid Anhydrides
Typical Ranges (v ~ in cm -1 )
Assignment
Range
Comments
C=O st sy
1870–1770
Strong. In Raman, weak to medium
C=O st as
1800–1720
Strong. In Raman, weak to medium
Subranges:
≈1820, ≈1760
Linear anhydrides, higher band stronger
≈1850, ≈1775
5-Ring, lower band stronger
≈1800, ≈1760
6-Ring, lower band stronger
C–O–C st
1300–900
Strong, several bands
≈1040
Linear anhydrides
≈920
Cyclic anhydrides
Examples (v ~ in cm -1 )
O
O
O
1825
1748
O
O
O
1810
1740
1045
1040
O
O
O
1803
1743
O
O
O
1780
1725
O
O
O
1790
1727
1035
1015
995
O
O
O
1865
1782
920
%T
400
800
1200
1600
2000
2800
3600
C=O st as
C=O st sy
C–O–C st