What absorbs at 1275 cm⁻¹ in an FTIR spectrum?
A band near 1275 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 1275 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 | 9 | 9 | 1.0 |
| Acetate | 9 | 9 | 1.0 |
| Methoxy (OCH3) | 7 | 7 | 1.0 |
| C-O single bond | 6 | 6 | 1.0 |
| Alkyl C-H | 5 | 5 | 1.0 |
| Carboxyl (COOH) | 4 | 4 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Ester | 3 | 3 | 1.0 |
| Ketone | 2 | 2 | 1.0 |
| Carbonyl (C=O) | 2 | 2 | 1.0 |
| Silicon carbon | 2 | 2 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Ring structure | 1 | 0 | 0.8 |
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 |
|---|---|---|---|
| PVA | 1275, 1660, 2930 | Acetate, Methacrylate, 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 1275 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
-
Hydroxyl (O-H) confidence 1.0
“1275cm-1 Changes in functional groups (chemical structure) were studied via the band generally assigned to phenols.”
Fossil cutin of Johnstonia coriacea (Corystospermaceae, Upper Triassic, Cacheuta, Argentina) DOI: 10.1016/j.coal.2018.02.016 -
Alkyl C-H confidence 1.0
“3 cm(cid:1)1 VSE is observed for the 2997, 2952, and 2919 bands assigned cm(cid:1)1 to the CH stretching modes, the 1275 and 1245 bands C(cid:1)(cid:1)O assigned to the stretching modes, and the 1194 and cm(cid:1)1 C(cid:1)(cid:1)C 1151 ban”
Vibrational Stark effect (VSE) on the infrared spectrum of a poly(methyl methacrylate) thin film DOI: 10.1016/j.vibspec.2015.03.006 -
Silicon carbon confidence 1.0
“Among the CVD ashed films, the lower roughness 3 (cid:1)2968 cm-1(cid:2) (cid:1)1275 cm-1(cid:2) stretching and Si-CH bending modes, a value in the case of the O 2-plasma-exposed film may be attributed to”
Vinogradova 等 - 2008 - Application of deuterium exchange to analyze moist DOI: 10.1149/1.2947786(cid:2) -
Hydroxyl (O-H) confidence 1.0
“cm-1 The small peak at 1450 was assigned to C-OH bending deformation, and the peak at 1275 The small peak at 1450 cm-1 was assigned to C-OH bending deformation, and the peak at 1275”
Application of Functional Data Analysis and FTIR-ATR Spectroscopy to Discriminate Wine Spirits Ageing Technologies DOI: 10.3390/math8060896 -
Hydroxyl (O-H) confidence 1.0
“(cid:2) FC stretch 1293sh 1282 (0.20) CO phenolic stretch 1275 1277 (0.99)”
Hydrogen Bonding in Human Manganese Superoxide Dismutase Containing 3-Fluorotyrosine DOI: 10.1529/biophysj.105.060616 -
Acetate confidence 1.0
“CH wagging of cellulose and hemicelluloses 1335 - 1315 2 Characteristic peak of lignin 1275 C-O of acetyl in pectin or hemicelluloses 1240 anti-symmetrical deformation of the C-O-C band 1160 C-O stretching and ring vibrational modes 1125-89”
Qualitative and quantitative assessment of water sorption in natural fibres using ATR-FTIR spectroscopy DOI: 10.1016/j.carbpol.2013.09.023 -
Acetate confidence 1.0
“cm-1, 30 between 3000-2860 the aromatic C-H stretch at 3060 the carboxyl (C=O) stretch at cm-1, cm-1, 31 1700 aromatic ring stretching modes at 1590 and 1515 the C-O-(C) stretch at 1275 cm-1 cm-1.”
Cibati 等 - 2017 - Assessment of Miscanthus x giganteus derived bioch DOI: 10.1016/j.jclepro.2017.06.114 -
Acetate confidence 1.0
“The FTIR spectrum has presented broad 1750cm-1 1275cm-1 3650cm-1 and 1200 to ranging from 1710 to bands in the frequency ranging from 3100 to (νC=O) arise due to the stretching vibration of carbonyl attributed to both contributions of hydro”
Costa 等 - 2012 - Engineered Hybrid Scaffolds of Poly(vinyl alcohol) DOI: 10.1155/2012/718470
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