Spectrochemistry: History
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Spectrochemistry is the application of spectroscopy in several fields of chemistry. It includes analysis of spectra in chemical terms, and use of spectra to derive the structure of chemical compounds, and also to qualitatively and quantitively analyze their presence in the sample. It is a method of chemical analysis that relies on the measurement of wavelengths and intensity of electromagnetic radiation.

  • chemical analysis
  • spectrochemistry
  • spectroscopy

1. History

Isaac Newton - English mathematician and Physicist
Joseph Von Fraunhofer- Bavarian Physicist
Gustav Kirchhoff - German Physicist
Thomas Young - British Polymath

It was not until 1666 that Isaac Newton showed that white lights from the sun could be dissipated into a continuous series of colors. So Newton introduced the concept which he called spectrum to describe this phenomenon. He used a small aperture to define the beam of light, a lens to collimate it, a glass prism to disperse it, and a screen to display the resulting spectrum. Newton's analysis of light was the beginning of the science of spectroscopy. Later, It became clear that the Sun's radiation might have components outside the visible portion of the spectrum. In 1800 William Hershel showed that the sun's radiation extended into infrared, and in 1801 John Wilhelm Ritter also made a similar observation in the ultraviolet. Joseph Von Fraunhofer extended Newton's discovery by observing the sun's spectrum when sufficiently dispersed was blocked by a fine dark lines now known as Fraunhofer lines. Fraunhofer also developed diffracting grating, which disperses the lights in much the same way as does a glass prism but with some advantages. the grating applied interference of lights to produce diffraction provides a direct measuring of wavelengths of diffracted beams. So by extending Thomas Young's study which demonstrated that a light beam passes slit emerges in patterns of light and dark edges Fraunhofer was able to directly measure the wavelengths of spectral lines. However, despite his enormous achievements, Fraunhofer was unable to understand the origins of the special line in which he observed. It was not until 33 years after his passing that Gustav Kirchhoff established that each element and compound has its unique spectrum and that by studying the spectrum of an unknown source, one could determine its chemical compositions, and with these advancements, spectroscopy became a truly scientific method of analyzing the structures of chemical compounds. Therefore, by recognizing that each atom and molecule has its spectrum Kirchhoff and Robert Bunsen established spectroscopy as a scientific tool for probing atomic and molecular structures and founded the field of spectrochemical analysis for analyzing the composition of materials.[1]

Robert Bunsen - German Chemist

2. IR Spectra Tables & Charts

IR Spectrum Table by Frequency[2]

Frequency Range Absorption (cm−1) Appearance Group Compound Class Comments
4000–3000 cm−1 3700-3584 medium, sharp O-H stretching alcohol free
  3550-3200 strong, broad O-H stretching alcohol intermolecular bonded
  3500 medium N-H stretching primary amine  
  3400-3300 medium N-H stretching aliphatic primary amine  
  3350-3310 medium N-H stretching secondary amine  
  3300-2500 strong, broad O-H stretching carboxylic acid usually centered on 3000 cm−1
  3200-2700 weak, broad O-H stretching alcohol intramolecular bonded
  3000-2800 strong, broad N-H stretching amine salt  
3000–2500 cm−1          
3000–2500 cm−1 3333-3267 strong, sharp C-H stretching alkyne  
  3100-3000 medium C-H stretching alkene  
  3000-2840 medium C-H stretching alkane  
  2830-2695 medium C-H stretching aldehyde doublet
  2600-2550 weak S-H stretching thiol  
2400–2000 cm−1          
2400–2000 cm−1 2349 strong O=C=O stretching carbon dioxide  
  2275-2250 strong, broad N=C=O stretching isocyanate  
  2260-2222 weak CΞN stretching nitrile  
  2260-2190 weak CΞC stretching alkyne disubstituted
  2175-2140 strong S-CΞN stretching thiocyanate  
  2160-2120 strong N=N=N stretching azide  
  2150   C=C=O stretching ketene  
  2145-2120 strong N=C=N stretching carbodiimide  
  2140-2100 weak CΞC stretching alkyne monosubstituted
  2140-1990 strong N=C=S stretching isothiocyanate  
  2000-1900 medium C=C=C stretching allene  
  2000   C=C=N stretching ketenimine  
2000–1650 cm−1          
2000–1650 cm−1 2000-1650 weak C-H bending aromatic compound overtone
  1818 strong C=O stretching anhydride  
  1815-1785 strong C=O stretching acid halide  
  1800-1770 strong C=O stretching conjugated acid halide  
  1775 strong C=O stretching conjugated anhydride  
  1770-1780 strong C=O stretching vinyl / phenyl ester  
  1760 strong C=O stretching carboxylic acid monomer
  1750-1735 strong C=O stretching esters 6-membered lactone
  1750-1735 strong C=O stretching δ-lactone γ: 1770
  1745 strong C=O stretching cyclopentanone  
  1740-1720 strong C=O stretching aldehyde  
  1730-1715 strong C=O stretching α,β-unsaturated ester or formates
  1725-1705 strong C=O stretching aliphatic ketone or cyclohexanone or cyclopentenone
  1720-1706 strong C=O stretching carboxylic acid dimer
  1710-1680 strong C=O stretching conjugated acid dimer
  1710-1685 strong C=O stretching conjugated aldehyde  
  1690 strong C=O stretching primary amide free (associated: 1650)
  1690-1640 medium C=N stretching imine / oxime  
  1685-1666 strong C=O stretching conjugated ketone  
  1680 strong C=O stretching secondary amide free (associated: 1640)
  1680 strong C=O stretching tertiary amide free (associated: 1630)
  1650 strong C=O stretching δ-lactam γ: 1750-1700 β: 1760-1730
1670–1600 cm−1          
1670–1600 cm−1 1678-1668 weak C=C stretching alkene disubstituted (trans)
  1675-1665 weak C=C stretching alkene trisubstituted
  1675-1665 weak C=C stretching alkene tetrasubstituted
  1662-1626 medium C=C stretching alkene disubstituted (cis)
  1658-1648 medium C=C stretching alkene vinylidene
  1650-1600 medium C=C stretching conjugated alkene  
  1650-1580 medium N-H bending amine  
  1650-1566 medium C=C stretching cyclic alkene  
  1648-1638 strong C=C stretching alkene monosubstituted
  1620-1610 strong C=C stretching α,β-unsaturated ketone  
1600–1300 cm−1          
1600–1300 cm−1 1550-1500 strong N-O stretching nitro compound  
  1465 medium C-H bending alkane methylene group
  1450 medium C-H bending alkane methyl group
  1390-1380 medium C-H bending aldehyde  
  1385-1380 medium C-H bending alkane gem dimethyl
1400–1000 cm−1          
1400–1000 cm−1 1440-1395 medium O-H bending carboxylic acid  
  1420-1330 medium O-H bending alcohol  
  1415-1380 strong S=O stretching sulfate  
  1410-1380 strong S=O stretching sulfonyl chloride  
  1400-1000 strong C-F stretching fluoro compound  
  1390-1310 medium O-H bending phenol  
  1372-1335 strong S=O stretching sulfonate  
  1370-1335 strong S=O stretching sulfonamide  
  1350-1342 strong S=O stretching sulfonic acid anhydrous
  1165-1150       hydrate: 1230-1120
  1350-1300 strong S=O stretching sulfone  
  1342-1266 strong C-N stretching aromatic amine  
  1310-1250 strong C-O stretching aromatic ester  
  1275-1200 strong C-O stretching alkyl aryl ether  
  1250-1020 medium C-N stretching amine  
  1225-1200 strong C-O stretching vinyl ether  
  1210-1163 strong C-O stretching ester  
  1205-1124 strong C-O stretching tertiary alcohol  
  1150-1085 strong C-O stretching aliphatic ether  
  1124-1087 strong C-O stretching secondary alcohol  
  1085-1050 strong C-O stretching primary alcohol  
  1070-1030 strong S=O stretching sulfoxide  
  1050-1040 strong, broad CO-O-CO stretching anhydride  
1000–650 cm−1          
1000–650 cm−1 995-985 strong C=C bending alkene monosubstituted
  980-960 strong C=C bending alkene disubstituted (trans)
  895-885 strong C=C bending alkene vinylidene
  850-550 strong C-Cl stretching halo compound  
  840-790 medium C=C bending alkene trisubstituted
  730-665 strong C=C bending alkene disubstituted (cis)
  690-515 strong C-Br stretching halo compound  
  600-500 strong C-I stretching halo compound  
900–700 cm−1          
900–700 cm−1 880 ± 20 strong C-H bending 1,2,4-trisubstituted  
  810 ± 20        
  880 ± 20 strong C-H bending 1,3-disubstituted  
  780 ± 20        
  (700 ± 20)        
  810 ± 20 strong C-H bending 1,4-disubstituted or  
  780 ± 20 strong C-H bending 1,2,3-trisubstituted  
  (700 ± 20)        
  755 ± 20 strong C-H bending 1,2-disubstituted  
  750 ± 20 strong C-H bending monosubstituted  
  700 ± 20     benzene derivative  

IR Spectra Table by Compound Class[3]

Compound Class Group Absorption (cm−1) Appearance Comments
acid halide C=O stretching 1815-1785 strong  
alcohols O-H stretching 3700-3584 medium, sharp free
  O-H stretching 3550-3200 strong, broad intermolecular bonded
  O-H stretching 3200-2700 weak, broad intramolecular bonded
  O-H bending 1420-1330 medium  
aldehyde C-H stretching 2830-2695 medium doublet
  C=O stretching 1740-1720 strong  
  C-H bending 1390-1380 medium  
aliphatic ether C-O stretching 1150-1085 strong  
aliphatic ketone C=O stretching 1725-1705 strong or cyclohexanone or cyclopentenone
aliphatic primary amine N-H stretching 3400-3300 medium  
alkane C-H stretching 3000-2840 medium  
  C-H bending 1465 medium methylene group
  C-H bending 1450 medium methyl group
  C-H bending 1385-1380 medium gem dimethyl
  C-H stretching 3100-3000 medium  
  C=C stretching 1678-1668 weak disubstituted (trans)
  C=C stretching 1675-1665 weak trisubstituted
  C=C stretching 1675-1665 weak tetrasubstituted
  C=C stretching 1662-1626 medium disubstituted (cis)
  C=C stretching 1658-1648 medium vinylidene
  C=C stretching 1648-1638 strong monosubstituted
  C=C bending 995-985 strong monosubstituted
  C=C bending 980-960 strong disubstituted (trans)
  C=C bending 895-885 strong vinylidene
  C=C bending 840-790 medium trisubstituted
  C=C bending 730-665 strong disubstituted (cis)
alkyl aryl ether C-O stretching 1275-1200 strong  
alkyne C-H stretching 3333-3267 strong, sharp  
  CΞC stretching 2260-2190 weak disubstituted
  CΞC stretching 2140-2100 weak monosubstituted
allene C=C=C stretching 2000-1900 medium  
amine N-H bending 1650-1580 medium  
  C-N stretching 1250-1020 medium  
amine salt N-H stretching 3000-2800 strong, broad  
anhydride C=O stretching 1818 strong  
  CO-O-CO stretching 1050-1040 strong, broad  
aromatic amine C-N stretching 1342-1266 strong  
aromatic compound C-H bending 2000-1650 weak overtone
aromatic ester C-O stretching 1310-1250 strong  
azide N=N=N stretching 2160-2120 strong  
benzene derivative   700 ± 20    
carbodiimide N=C=N stretching 2145-2120 strong  
carbon dioxide O=C=O stretching 2349 strong  
carboxylic acid O-H stretching 3300-2500 strong, broad usually centered on 3000 cm−1
  C=O stretching 1760 strong monomer
  C=O stretching 1720-1706 strong dimer
  O-H bending 1440-1395 medium  
conjugated acid C=O stretching 1710-1680 strong dimer
conjugated acid halide C=O stretching 1800-1770 strong  
conjugated aldehyde C=O stretching 1710-1685 strong  
conjugated alkene C=C stretching 1650-1600 medium  
conjugated anhydride C=O stretching 1775 strong  
conjugated ketone C=O stretching 1685-1666 strong  
cyclic alkene C=C stretching 1650-1566 medium  
cyclopentanone C=O stretching 1745 strong  
ester C-O stretching 1210-1163 strong  
esters C=O stretching 1750-1735 strong 6-membered lactone
fluoro compound C-F stretching 1400-1000 strong  
halo compound C-Cl stretching 850-550 strong  
  C-Br stretching 690-515 strong  
  C-I stretching 600-500 strong  
imine / oxime C=N stretching 1690-1640 medium  
isocyanate N=C=O stretching 2275-2250 strong, broad  
isothiocyanate N=C=S stretching 2140-1990 strong  
ketene C=C=O stretching 2150    
ketenimine C=C=N stretching 2000    
monosubstituted C-H bending 750 ± 20 strong  
nitrile CΞN stretching 2260-2222 weak  
nitro compound N-O stretching 1550-1500 strong  
none   3330-3250    
none   1870-1540    
none   1750    
none   1720    
none   1372-1290    
none   1375    
none   1370-1365    
none   1200-1185    
none   1204-1177    
none   1195-1168    
none   1170-1155    
none   1165-1150   hydrate: 1230-1120
none   1160-1120    
none   1075-1020    
none   1075-1020    
none   915-905    
none   810 ± 20    
none   780 ± 20    
none   (700 ± 20)    
none   (700 ± 20)    
phenol O-H bending 1390-1310 medium  
primary alcohol C-O stretching 1085-1050 strong  
primary amide C=O stretching 1690 strong free (associated: 1650)
  N-H stretching 3500 medium  
secondary alcohol C-O stretching 1124-1087 strong  
secondary amide C=O stretching 1680 strong free (associated: 1640)
secondary amine N-H stretching 3350-3310 medium  
sulfate S=O stretching 1415-1380 strong  
sulfonamide S=O stretching 1370-1335 strong  
sulfonate S=O stretching 1372-1335 strong  
sulfone S=O stretching 1350-1300 strong  
sulfonic acid S=O stretching 1350-1342 strong anhydrous
sulfonyl chloride S=O stretching 1410-1380 strong  
sulfoxide S=O stretching 1070-1030 strong  
tertiary alcohol C-O stretching 1205-1124 strong  
tertiary amide C=O stretching 1680 strong free (associated: 1630)
thiocyanate S-CΞN stretching 2175-2140 strong  
thiol S-H stretching 2600-2550 weak  
vinyl / phenyl ester C=O stretching 1770-1780 strong  
vinyl ether C-O stretching 1225-1200 strong  
α,β-unsaturated ester C=O stretching 1730-1715 strong or formates
α,β-unsaturated ketone C=C stretching 1620-1610 strong  
δ-lactam C=O stretching 1650 strong γ: 1750-1700 β: 1760-1730
δ-lactone C=O stretching 1750-1735 strong γ: 1770
1,2,3-trisubstituted C-H bending 780 ± 20 strong  
  C-H bending 880 ± 20 strong  
1,2-disubstituted C-H bending 755 ± 20 strong  
  C-H bending 880 ± 20 strong  
1,4-disubstituted or C-H bending 810 ± 20 strong  

To use an IR spectrum table, first need to find the frequency or compound in the first column, depending on which type of chart that is being used. Then find the corresponding values for absorption, appearance and other attributes. The value for absorption is usually in cm−1.


3. Applications

3.1. Evaluation of Dual - Spectrum IR Spectrogram System on Invasive Ductal Carcinoma (IDC) Breast Cancer

Breast Cancer Gross Appearance

Invasive Ductal Carcinoma (IDC) is one of the common types of breast cancer which accounts for 8 out of 10 of all invasive breast cancers. According to the American Cancer Society, more than 180,000 women in the United States find out that they have breast cancers each year, and most are diagnosed with this specific type of cancer.[4] While it is essential to detect breast cancer early to reduce the death rate there may be already more than 10,000,000 cells in breast cancer when it can be observed by x-ray mammograms. however, the IR Spectrum proposed by Szu et al seems to be more promising in detecting breast cancer cells several months ahead of a mammogram. Clinical tests have been carried out with approval of Institutional Review Board of National Taiwan University Hospital. So from August 2007 to June 2008 35 patients aged between (30-66) with an average age of 49 were enlisted in this project. the results established that about 63% of the success rate could be achieved with the cross-sectional data. Therefore the results concluded that breast cancers may be detected more accurately by cross-referencing S1 maps of multiple three-points.[5]

3.2. Molecular Spectroscopic Methods to Elucidation of Lignin Structure

A Ligninin plant cell is a complex amorphous polymer and it is biosynthesized from three aromatic alcohols, namely P-Coumaryl, Coniferyl, and Sinapyl alcohols. Lignin is a highly branched polymer and accounts for 15-30% by weight of lignocellulosic biomass (LCBM), so the structure of lignin will vary significantly according to the type of LCBM and the composition will depend on the degradation process.[6] This biosynthesis process is mainly consists of radical coupling reactions and it generates a particular lignin polymer in each plant species. So due to having a complex structure, various molecular spectroscopic methods have been applied to resolve the aromatic units and different interunit linkages in lignin from distinct plant species.[7]

General Lignin Structure

The content is sourced from: https://handwiki.org/wiki/Chemistry:Spectrochemistry


  1. "The Era of Classical Spectroscopy". https://web.mit.edu/spectroscopy/history/history-classical.html. 
  2. "IR spectrum table & chart". https://www.sigmaaldrich.com/technical-documents/articles/biology/ir-spectrum-table.html. 
  3. "IR spectrum table & chart". https://www.sigmaaldrich.com/technical-documents/articles/biology/ir-spectrum-table.html. 
  4. "Invasive Ductal Carcinoma: Diagnosis, Treatment, and More". 21 January 2020. https://www.breastcancer.org/symptoms/types/idc. 
  5. Lee, Chuang, Hsieh, Lee, Lee, Shih, Lee, Huang, Chang, Chen, Chia-Yen, Ching-Cheng, Hsin-Yu, Wan-Rou, Ching-Yen, Shyang-Rong, Si-Chen, Chiun-Sheng, Yeun-Chung, Chung-Ming Chen (14 June 2011). EVALUATION OF DUAL-SPECTRUM IR SPECTROGRAM SYSTEM ON INVASIVE DUCTAL CARCINOMA (IDC) BREAST CANCER. Institute of Biomedical Engineering, National Taiwan University, Taiwan. pp. 427–433. 
  6. Lu, Lu, Hu, Xie, Wei, Fan, Yao, Yong-Chao, Hong-Qin, Feng-Jin, Xian-Yong, Xing (29 November 2017). "Structural Characterization of Lignin and Its Degradation Products with Spectroscopic Methods". https://www.hindawi.com/journals/jspec/2017/8951658/. 
  7. You, Xu, Tingting, Feng (5 October 2016). "Applications of Molecular Spectroscopic Methods to the Elucidation of Lignin Structure". https://www.intechopen.com/books/applications-of-molecular-spectroscopy-to-current-research-in-the-chemical-and-biological-sciences/applications-of-molecular-spectroscopic-methods-to-the-elucidation-of-lignin-structure. 
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