Page 1 of 7
Name: ___________________________________________
Lab (Day & Time): __________________________________
Worksheet 2 – IR Spectroscopy
Task 1: Predict the DIAGNOSTIC absorptions expected in the IR spectra of the following compounds.
Compound Structure Vibrating bonds Predicted range (cm-1)
(from reference table)
1 C=O stretch 1700-1750
sp3C−O 1000 – 1100
sp2C−O 1250-1350
absence of a broad absorption between
2200 – 3600 to rule out the O−H stretch of
an alcohol or a carboxylic acid
2
3
4
5
6
This study source was downloaded by 100000898062787 from CourseHero.com on 09-30-2025 23:59:43 GMT -05:00
https://www.coursehero.com/file/251850692/Worksheet-2-IR-Spectroscopy-Updated-Spring-2024pdf/
, Page 2 of 7
Task 2: Systematically analyze the IR spectra 1- 4 presented on the following pages and match them
with the structures of compounds indicated below. Label the diagnostic absorptions on the spectra
and then complete the table below each spectrum.
Note:
• The number of structures provided below is more than the number of spectra provided.
• The structures indicated below are constitutional isomers of C4H6O2.
Spectrum 1:
FTIR
NEAT
100
90
80
3093.3 1625.7
592.0
70
% Transmittance
406.9
848.5 636.4
60
977.7
1294.0
50
877.4
950.7
40 1020.2
30
1646.9
1371.1 1137.8
20
1762.6 1218.8
4500 4250 4000 3750 3500 3250 3000 2750 2500 2250 2000 1750 1500 1250 1000 750 500 250
Wavenumbers (cm-1)
© 2018, Sigma-Aldrich Co.
ALL RIGHTS RESERVED
Bond vibration Expected frequency range (cm-1) Observed absorption (cm-1)
(from IR absorption table)
Functional group(s): ____________________________________
Structure:
This study source was downloaded by 100000898062787 from CourseHero.com on 09-30-2025 23:59:43 GMT -05:00
https://www.coursehero.com/file/251850692/Worksheet-2-IR-Spectroscopy-Updated-Spring-2024pdf/
Name: ___________________________________________
Lab (Day & Time): __________________________________
Worksheet 2 – IR Spectroscopy
Task 1: Predict the DIAGNOSTIC absorptions expected in the IR spectra of the following compounds.
Compound Structure Vibrating bonds Predicted range (cm-1)
(from reference table)
1 C=O stretch 1700-1750
sp3C−O 1000 – 1100
sp2C−O 1250-1350
absence of a broad absorption between
2200 – 3600 to rule out the O−H stretch of
an alcohol or a carboxylic acid
2
3
4
5
6
This study source was downloaded by 100000898062787 from CourseHero.com on 09-30-2025 23:59:43 GMT -05:00
https://www.coursehero.com/file/251850692/Worksheet-2-IR-Spectroscopy-Updated-Spring-2024pdf/
, Page 2 of 7
Task 2: Systematically analyze the IR spectra 1- 4 presented on the following pages and match them
with the structures of compounds indicated below. Label the diagnostic absorptions on the spectra
and then complete the table below each spectrum.
Note:
• The number of structures provided below is more than the number of spectra provided.
• The structures indicated below are constitutional isomers of C4H6O2.
Spectrum 1:
FTIR
NEAT
100
90
80
3093.3 1625.7
592.0
70
% Transmittance
406.9
848.5 636.4
60
977.7
1294.0
50
877.4
950.7
40 1020.2
30
1646.9
1371.1 1137.8
20
1762.6 1218.8
4500 4250 4000 3750 3500 3250 3000 2750 2500 2250 2000 1750 1500 1250 1000 750 500 250
Wavenumbers (cm-1)
© 2018, Sigma-Aldrich Co.
ALL RIGHTS RESERVED
Bond vibration Expected frequency range (cm-1) Observed absorption (cm-1)
(from IR absorption table)
Functional group(s): ____________________________________
Structure:
This study source was downloaded by 100000898062787 from CourseHero.com on 09-30-2025 23:59:43 GMT -05:00
https://www.coursehero.com/file/251850692/Worksheet-2-IR-Spectroscopy-Updated-Spring-2024pdf/
