What absorbs at 2012 cm⁻¹ in an FTIR spectrum?
A band near 2012 cm⁻¹ can point to several functional groups. Below are the most likely assignments, ranked by how much published evidence supports each — every one traceable to literature (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.
Backed by 8 cited sources
Quick answer
A band near 2012 cm⁻¹ is usually interpreted by checking which functional groups repeatedly co-occur there in the literature, then confirming at least one or two additional peaks in the same sample. This page ranks those assignments by accumulated evidence rather than by a single fixed textbook rule.
Possible functional-group assignments
| Functional group | Supporting facts | Cited sources | Top confidence |
|---|---|---|---|
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 1 | 1.0 |
| Adsorbed carbon monoxide | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| N n bond | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| hemicellulose | 2012, 1730, 897 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| AgNPs | 2012, 1232, 1048 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| polyvinylpyrrolidone | 2012, 1660, 1700 | Alkyl C-H, Hydroxyl (O-H), Carboxyl (COOH) | 1 |
| polyvinyl alcohol | 2012, 1141, 1640 | Hydroxyl (O-H), Alkyl C-H, Carboxyl (COOH) | 1 |
| citric acid | 2012, 1725, 1732 | Carboxyl (COOH), Hydroxyl (O-H) | 1 |
| soil | 2012, 575, 1240 | Hydroxyl (O-H), Alkyl C-H, Carboxyl (COOH) | 1 |
Materials are shown only when the same literature pool supports this band and at least one additional characteristic peak.
Spectrum logic
This band becomes meaningful only when read with its neighboring peaks. In practice, analysts first look at the assignments above, then check whether the same sample also shows other peaks expected for the same structural motif. A lone band near 2012 cm⁻¹ is usually not enough for material identification by itself.
Real-world usage
This type of query is common in polymer identification, unknown plastic screening, QC troubleshooting, recycled-material verification, and literature-backed peak assignment review.
Common mistakes
- Treating one isolated band as proof of a material without checking at least one or two supporting peaks.
- Ignoring overlap: multiple functional groups can contribute near the same wavenumber.
- Skipping validation when additives, blends, oxidation, or contamination may distort the spectrum.
Verification advice
When ambiguity remains, validate the hypothesis with DSC, GC-MS, or TGA, especially for blends, degraded samples, and filled polymers.
Literature behind these assignments
-
Alkyl C-H confidence 1.0
“However, absorption bands observed between 2011.5 and 2357.3 are due to cm-1 cm-1 the stretching of C-H bonds [20].”
Unique Halloysite Nanotubes–Polyvinyl Alcohol– Polyvinylpyrrolidone Composite Complemented with Physico–Chemical Characterization DOI: 10.3390/polym9060207 -
Alkyl C-H confidence 1.0
“Many differences can be noted in this region, which 1 050-1 000 region, which should be attributed to the constitutes a very good analytical area (Sahoo et al., deformation vibrations of the C-H group and the stretching 2012).”
Kachel-Jakubowska 等 - 2017 - Analysis of the physicochemical properties of post DOI: 10.1515/intag-2016-0042 -
N n bond confidence 1.0
“The peakposition n n n 2012.”
Long 等 - 2012 - From synthetic to biogenic Mg-containing calcites DOI: 10.1039/c2cp22453d -
Hydroxyl (O-H) confidence 1.0
“Evaluation of leaf aqueous extract and synthesized silver & Mathath Roni Kadarkarai Murugan & Chellasamy Panneerselvam Jayapal Subramaniam Received: 2 November 2012/Accepted: 22 November 2012/Published online: 13 December 2012 # Springer-Ve”
Roni 等 - 2013 - Evaluation of leaf aqueous extract and synthesized DOI: 10.1007/s00436-012-3220-3 -
Metal oxygen confidence 1.0
“Those aggregates consist of few inand 673 all attributed to Cu-O vibrations of copper oxide/hydividual CuNPs and are homogenously dispersed on the investigated droxide vibrational bands (Ethiraj&Kang, 2012).”
Hydrothermal synthesis of bacterial cellulose–copper oxide nanocomposites and evaluation of their antimicrobial activity DOI: 10.1016/j.carbpol.2017.09.081 -
Carboxyl (COOH) confidence 1.0
“The presence of ester bonds may be indicated by the prescm(cid:3)1 films ence of a small shoulder around 1730 in with citric acid C]O (Coma et al., 2003), which corresponds to ester stretching & vibration (Dastidar Netravali, 2012;”
Azeredo 等 - 2015 - Wheat straw hemicellulose films as affected by cit DOI: 10.1016/j.foodhyd.2015.04.005 -
Water (H2O) confidence 1.0
“Apparent structure in the laser output spectrum largely results from atmospheric water vapor (principle water absorption bands from the HITRAN2012 database included for refercm¡1 ence).”
Childs 等 - 2015 - Sensitivity Advantage of QCL Tunable-Laser Mid-Inf DOI: 10.1080/05704928.2015.1075208 -
N-O bond confidence 1.0
“temperatures, with some soils like Ngata, Menashe and Jerusalem identified at 1426 and 1478 which correspond to the area of C cm(cid:0) 1 stretches (Oren and Chefetz, 2012), although the one at 1426 showing increases in this ratio when heat”
Heat-induced changes in soil water-extractable organic matter characterized using fluorescence and FTIR spectroscopies coupled with dimensionality reduction methods DOI: 10.1016/j.geoderma.2023.116347
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