What absorbs at 1210 cm⁻¹ in an FTIR spectrum?
A band near 1210 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 1210 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 |
|---|---|---|---|
| Methacrylate | 12 | 9 | 1.0 |
| Acetate | 12 | 9 | 1.0 |
| C-O single bond | 11 | 10 | 1.0 |
| Methoxy (OCH3) | 10 | 9 | 1.0 |
| Alkyl C-H | 7 | 6 | 1.0 |
| Amide | 6 | 4 | 1.0 |
| Hydroxyl (O-H) | 5 | 5 | 1.0 |
| Ester | 4 | 2 | 1.0 |
| Aromatic ring | 3 | 3 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| C n single bond | 3 | 3 | 1.0 |
| Ring structure | 3 | 3 | 1.0 |
| Carbonyl (C=O) | 3 | 1 | 1.0 |
| Alkene (C=C) | 2 | 2 | 1.0 |
| C c single bond | 2 | 1 | 1.0 |
| Ketone | 2 | 0 | 1.0 |
| Carboxyl (COOH) | 2 | 0 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| Fluorine (C-F) | 1 | 1 | 1.0 |
| C=n | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| S s | 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 |
|---|---|---|---|
| Chitosan | 1210, 1650, 1655 | Acetate, Methacrylate, C-O single bond | 1 |
| cotton | 1210, 1030, 1638 | Methacrylate, Acetate, C-O single bond | 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 1210 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
-
Ring structure confidence 1.0
“zole ring double-bond hydrogen C=CH, and the peak of Figure 3b shows the ATR-FTIR spectrum of PFSA cm-1 membrane, wherein 1210 and 1150 of the two peaks -mCFwere the symmetric and asymmetric stretching”
Thermal stability and lifetime of [AMIM]Cl-PFSA composite membranes DOI: 10.1007/s10973-016-6065-7 -
S s confidence 1.0
“In addition, the band f f cm-1 at 1183 in the S S and S S transitions, at shapes slightly changed, retaining an overall spectral 1 2 2 3 ∼1201 ∼1210 cm-1 and observed in all four transitions, feature;”
Suzuki 等 - 2008 - Monitoring water reactions during the S-state cycl DOI: 10.1021/bi801580e -
Amide confidence 1.0
“Moreover, the degree of cm21 as preabsorption peak should appear around 1250 increase in C-N single bond was greater than that of C vN Wixom.2 dicted by Here the absorption peak around 1210”
Wei - 2001 - Formation of beta-C3N4 crystals at low temperature DOI: 10.1063/1.1327603 -
Acetate confidence 1.0
“cm-1 (ring stretching), 1445 due to CH3 (stretching), 1303 and 1125 due to C-N cm-1 cm-1 (stretching), 1210 due to C-O-C (stretching), and 836, 755, and 693 due to C-H (out of plane bending of aromatic ring).”
Adam 等 - 2022 - Comparative Evaluation of Amlodipine Besylate Gene DOI: 10.14227/DT290422PGC2 -
Alkyl C-H confidence 1.0
“This 3stretchingvibration,whilethepeakat1210cm(cid:3)1 2-CH withCH Theproductyieldwas90.3%andthewatercontentwasfoundto C-H Access is corresponded to bending vibration.”
Metal chloride anion based ionic liquids: synthesis, characterization and evaluation of performance in hydrogen sulfide oxidative absorption DOI: 10.1039/d2ra01494g -
Phosphate (PO4) confidence 1.0
“Moreover, weak peaks at 1210 and 725 cm-1 are visible in the HAp spectrum (Figure 8, curve b), which can be assigned to P-O vibrations in pyrophosphate groups.”
Zirconia/Hydroxyapatite Composites Synthesized Via Sol-Gel: Influence of Hydroxyapatite Content and Heating on Their Biological Properties DOI: 10.3390/ma10070757 -
Alkyl C-H confidence 1.0
“The absorption bands in the ranges 2800-3000 and 1210 cm-1 are connected with the valence and deformation CH oscillations, respectively.”
Chekhovskii 等 - 2008 - Kinetics of C(x)N(y) formation on electrode surfac DOI: 10.2298/SOS0802147C -
Aromatic ring confidence 1.0
“In addition, physicochemical changes in the sample structure were clearly visible in the spectral curves between the untreated C_A and the treated sample C_A_ApI, at cm-1, the peak 1210 resulting from the elongation of the CO bond, which in”
Hydrothermal Synthesis of Chitosan and Tea Tree Oil on Plain and Satin Weave Cotton Fabrics DOI: 10.3390/ma15145034
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