1. CH 2-4 Example: Using Infra-Red (IR) Spectroscopy to ID an Unknown Compound
IR is an instrumental method used to identify some of the functional groups present in an organic compound.
The x-axis scale represents frequency in wavenumbers, and runs from cm-1

2. The absorption bands of different functional groups absorb at different frequencies and intensities.
(~3300 if terminal)
Keep it simple! Do not memorize the absorption frequencies, and do not “over-interpret” the IR spectrum. Focus on these four specific functional group(s).

3. Example #3: Unknown Structure Identification
Formula: C5H10O
Additional Info:
Three, 1o carbons
One, 3o carbon
Calculate Hydrogen Deficiency
Evaluate IR spectrum
Suggest possible structures

4. Example #3: Unknown Structure Identification
Formula: C5H10O
Additional Info: 3x1o carbons; 1x3o carbon
HD = 2
IR = carbonyl: C=O