What absorbs at 3313 cm⁻¹ in an FTIR spectrum?
A band near 3313 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 3313 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 |
|---|---|---|---|
| N h | 7 | 7 | 1.0 |
| Hydroxyl (O-H) | 5 | 5 | 1.0 |
| Hydrogen bond | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Amide | 2 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Water (H2O) | 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 |
|---|---|---|---|
| PVP | 3313, 2983, 1648 | Hydroxyl (O-H), Secondary amine | 1 |
| CMC | 3313, 1423, 1196 | Hydroxyl (O-H), Secondary amine | 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 3313 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
-
Water (H2O) confidence 1.0
“Thus the representative peak positions are found to be cm-1 cm-1 cm-1 represent two different existing forms of water molecules connected Li+, Na+, 3255 for FIWs of 3360 for FIWs of 3313 cm-1 with lithium andsodium.”
Ashraf 等 - 2021 - Identification and properties of ion-pairs in the DOI: 10.1016/j.molliq.2020.114891 -
Hydroxyl (O-H) confidence 1.0
“electrolytes O-H stretching 3313 3295 3264 3240 C-H stretching”
Investigations of biodegradable polymer blend electrolytes based on Cornstarch: PVP: NH4Cl and its potential application in solid-state batteries DOI: 10.1007/s10854-021-05266-1 -
Hydroxyl (O-H) confidence 1.0
“LLM confirmed rule peak-group candidate”
REMOVAL OF METAL IONS FROM AQUEOUS SOLUTIONS USING CARBOXYMETHYL CELLULOSE/SODIUM STYRENE SULFONATE GELS PREPARED BY RADIATION GRAFTING DOI: 10.1016/j.carbpol.2016.09.049 -
N h confidence 1.0
“The structure of the mol-1, molecule was confirmed by HRMS, which showed a peak at 923.36 g corresponding FTIR analysis of TPhPyP (Figure 2a) showed the weak band at 3313 cm-1 attributed 1H to the molecular weight (Figure S1) and spectrosco”
Synthesis of a New Co Metal–Organic Framework Assembled from 5,10,15,20-Tetrakis((pyridin-4-yl) phenyl)porphyrin “Co-MTPhPyP” and Its Application to the Removal of Heavy Metal Ions DOI: 10.3390/molecules28041816 -
confidence 1.0
“The peak at 3316 cm-1 (observed in mushrooms produced in WS, cm-1 3313 and 3301 for GM and OL, respectively) can be attributed to the N-H stretching vibration and shifted to 3313 and 3301 cm-1 for GM and OL, respectively) can be attributed”
Pleurotus Mushrooms Content in Glucans and Ergosterol Assessed by ATR-FTIR Spectroscopy and Multivariate Analysis DOI: 10.3390/foods9040535 -
N h confidence 1.0
“Explicit assignment: 'NH (3313 cm-1)'”
Bradley 等 - 2016 - Do the mechanical and chemical properties of Invis DOI: 10.1093/ejo/cjv003 -
N h confidence 1.0
“bound modes associated to the H-bonded amides: the NH stretching From this relationship the fraction X can be derived from cm-1, cm-1 bound band at 3313 the amide I at 1654 and the amide II at the values of and when they are known.”
Origin of Invariant Gel Melting Temperatures in the c-T Phase Diagram of an Organogel DOI: 10.1021/acs.langmuir.6b00995 -
Amide confidence 1.0
“bands at 3459 and 3363 cm-1, assigned to stretching vibrations of amine and hydroxyl groups of cm-1, 3459 and 3363 assigned to stretching vibrations of amine and hydroxyl groups of lorazepam lorazepam and asymmetric stretching of the amide”
Garbacz 等 - 2020 - Structural Characterization of Co-Crystals of Chlo DOI: 10.3390/pharmaceutics12070648
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