Alkane
SP3 C-H stretch just below 3000 cm-1
Alkene
SP2 CH stretch just above 3000 cm-1; C=C Stretch in 1600's (may be weak or absent); OOP bending for substitution
Alkyne
SP CH stretch - strong, sharp band around 3300 cm-1; CC triple bond stretch near 2150 cm-1
Alcohol
OH stretch - strong, much wider, loop bond before typical SP stretch
Carbonyl (Ketone)
C=O stretch - always has strong band around 1700-1750cm-1
Carboxylic Acids
C=O & OH bond (although OH bond is very different from that of alcohols - wider, lower frequency, and covers CH stretch region)
Aldehyde
C=O band at 1700's; CH bands at 2750 AND 2850cm-1
Ester
C=O band in 1700's & Ester basket (several strong bands from 1000 - 1300 cm-1)
Amine
N-H stretch (double peak; weaker than OH stretch, but in same region); NH Bend (weak peak) in 1600's
Amide
C=O stretch lower than other C=O bands but stronger C=C; NH band much stronger than amine but weaker than alcohol (still has double peak)
Nitrile
Sharp CN stretch at 2250 (slightly higher frequency than CC band at 2150 and sharper)
Aromatic
SP2 CH; Overtone and combination bands give substitution pattern; 2 to 4 bands from 1450-1600 cm-1; OOP bending