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Chapter 5. Infrared spectroscopy

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Analytical Methods in Chemical Analysis
This chapter is in the book Analytical Methods in Chemical Analysis

Abstract

Infrared (IR) spectroscopy is used for the identification of functional groups and hence plays a major role in elucidating the structure of an unknown compound. This branch of spectroscopy is widely used in research, industries, as well as in forensic and environmental analysis, as it is a simple, quick, and reliable method of analysis. All the functional groups give a band (strong, medium, weak) in IR spectra. IR spectroscopy deals with the IR region of electromagnetic spectrum. Although, IR spectra are often measured in terms of wave number from 12,500 to 400 cm−1; however, organic chemists are interested in analyzing the region, referred to as middle IR which ranges from 4,000 to 400 cm−1. The wave number is directly proportional to energy; the higher the energy of absorbed radiation, higher is the value of wave number. Wave number can be defined as inverse of wavelength, and its unit is cm−1:

v (cm−1)= 1/λ(cm)

In this chapter, we have discussed the different regions of infrared (IR) spectroscopy, basic principle governing IR spectroscopy, different modes of vibrations, and factors affecting IR frequency. The IR spectra have been displayed in the chapter at relevant place which makes it easier for the students to understand the topic, and they will learn the identification of different functional groups in a molecule.

Abstract

Infrared (IR) spectroscopy is used for the identification of functional groups and hence plays a major role in elucidating the structure of an unknown compound. This branch of spectroscopy is widely used in research, industries, as well as in forensic and environmental analysis, as it is a simple, quick, and reliable method of analysis. All the functional groups give a band (strong, medium, weak) in IR spectra. IR spectroscopy deals with the IR region of electromagnetic spectrum. Although, IR spectra are often measured in terms of wave number from 12,500 to 400 cm−1; however, organic chemists are interested in analyzing the region, referred to as middle IR which ranges from 4,000 to 400 cm−1. The wave number is directly proportional to energy; the higher the energy of absorbed radiation, higher is the value of wave number. Wave number can be defined as inverse of wavelength, and its unit is cm−1:

v (cm−1)= 1/λ(cm)

In this chapter, we have discussed the different regions of infrared (IR) spectroscopy, basic principle governing IR spectroscopy, different modes of vibrations, and factors affecting IR frequency. The IR spectra have been displayed in the chapter at relevant place which makes it easier for the students to understand the topic, and they will learn the identification of different functional groups in a molecule.

Chapters in this book

  1. Frontmatter I
  2. Preface V
  3. Contents VII
  4. List of authors IX
  5. About the editors XI
  6. Abbreviations XIII
  7. Section I: Analytical chemistry
  8. Chapter 1. Introduction to analytical chemistry 3
  9. Section II: Qualitative and quantitative aspects of analysis
  10. Chapter 2. Quantitative aspects of analysis 23
  11. Chapter 3. Data handling in qualitative and quantitative analysis 37
  12. Section III: Spectrochemical methods of analysis
  13. Chapter 4. UV–visible spectroscopy 59
  14. Chapter 5. Infrared spectroscopy 81
  15. Chapter 6. Flame atomic absorption and emission spectroscopy 117
  16. Section IV: Thermoanalytical Methods
  17. Chapter 7 Thermogravimetric (TG) and derivative thermogravimetric analysis (DTG) 147
  18. Chapter 8. Differential thermal analysis 169
  19. Section V: Electroanalytical Methods
  20. Chapter 9. pH Metry 179
  21. Chapter 10. Conductance 205
  22. Chapter 11 Electrochemistry 229
  23. Section VI: Separation methods and chromatography
  24. Chapter 12. Separation methods in analysis 263
  25. Chapter 13 Chromatographic methods 281
  26. Chapter 14. Chromatographic techniques 293
  27. Index 323
https://doi.org/10.1515/9783110794816-005

Chapters in this book

  1. Frontmatter I
  2. Preface V
  3. Contents VII
  4. List of authors IX
  5. About the editors XI
  6. Abbreviations XIII
  7. Section I: Analytical chemistry
  8. Chapter 1. Introduction to analytical chemistry 3
  9. Section II: Qualitative and quantitative aspects of analysis
  10. Chapter 2. Quantitative aspects of analysis 23
  11. Chapter 3. Data handling in qualitative and quantitative analysis 37
  12. Section III: Spectrochemical methods of analysis
  13. Chapter 4. UV–visible spectroscopy 59
  14. Chapter 5. Infrared spectroscopy 81
  15. Chapter 6. Flame atomic absorption and emission spectroscopy 117
  16. Section IV: Thermoanalytical Methods
  17. Chapter 7 Thermogravimetric (TG) and derivative thermogravimetric analysis (DTG) 147
  18. Chapter 8. Differential thermal analysis 169
  19. Section V: Electroanalytical Methods
  20. Chapter 9. pH Metry 179
  21. Chapter 10. Conductance 205
  22. Chapter 11 Electrochemistry 229
  23. Section VI: Separation methods and chromatography
  24. Chapter 12. Separation methods in analysis 263
  25. Chapter 13 Chromatographic methods 281
  26. Chapter 14. Chromatographic techniques 293
  27. Index 323
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