What absorbs at 3070 cm⁻¹ in an FTIR spectrum?
A band near 3070 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 3070 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 |
|---|---|---|---|
| Alkyl C-H | 8 | 6 | 1.0 |
| Hydroxyl (O-H) | 5 | 4 | 1.0 |
| Alkene (C=C) | 4 | 4 | 1.0 |
| N h | 3 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Aromatic ring | 2 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 0 | 1.0 |
| Methacrylate | 1 | 0 | 1.0 |
| C-O single bond | 1 | 0 | 1.0 |
| Acetate | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 3070 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
-
Alkene (C=C) confidence 1.0
“The participation of the double bonds in the formation of Michael addition product was clearly evident from the disappearance of typical alkene bands at 3070, 3040, cm-1 1637.5, 1620.8, 1464, 984.4, and 910.6 in the C-H products (Figure 1(C”
Goswami 等 - 2004 - One-pot synthesis of a novel water-soluble fullere DOI: 10.1021/cm0350232 -
Alkyl C-H confidence 1.0
“Furthermore, at 0.05 mol fraction, the spectra show a cm-1 cm-1 peaks at 2880 and 2945 are attributed to the CH 3 cm-1, C-H distinct peak at 3070 ascribed to the mode of the (ss) stretch and the Fermi resonance (FR) of the CH bending 3”
GasLiquid Interface of Hydrophobic and Hydrophilic Room-Temperature Ionic Liquids and Benzene: Sum Frequency Generation and Surface Tension Studies DOI: 10.1021/jp803177w -
Hydroxyl (O-H) confidence 1.0
“Pure enstatite only exhibits two major O-H absorption cm-1, whereas samples containing bands at 3070 and 3361”
Stalder - 2004 - Influence of Fe, Cr and Al on hydrogen incorporati DOI: 10.1127/0935-1221/2004/0016-0703 -
Hydroxyl (O-H) confidence 1.0
“Figure 4 shows band arising from OH stretching vibrations of hydrogencm-1 ∼3070”
Bujok 等 - 2019 - Applicability of FTIR-ATR Method to Measure Carbon DOI: 10.1155/2019/2181370 -
confidence 1.0
“In particular, the characteristic peaks at 3349 cm-1 for N-H bonds, 3070 cm-1 for alkene C-H bonds, and 2858 and 2538 cm-1 for alkane C-H bonds became gradually apparent when the temperature was above 110 °C (Figure 10b).”
Synthesis and Characterization of Linear Polyisoprene Supramolecular Elastomers Based on Quadruple Hydrogen Bonding DOI: 10.3390/polym12010110 -
Alkyl C-H confidence 1.0
“The spectrum of the archaeological resinous sample indicated a composition very similar to that of modern colophony: shoulder cm-1 at 3070 associated with the vibration of the CH bond in a vinyl group CH2=CRR' and present only in diterpenic”
Ferrant 等 - 2022 - An innovative multi-analytical strategy to assess DOI: 10.1016/j.culher.2022.04.007 -
Water (H2O) confidence 1.0
“At 3098 and 3070 cm-1 cm-1 and at 3220 are related to the absorbed water and are assigned to the O-H 3414 stretch of the hydrogen-bonded O-H groups intramolecular and intermolecular, respectively.”
Gomes 等 - 2007 - Characterization of partially sulfonated polyoxadi DOI: 10.1016/j.memsci.2007.02.046 -
Alkene (C=C) confidence 1.0
“esters,lactones) the cycling ring structure or in its side chains produces (]CH ]C=O(acids) 1715 1715 the weak bands positioned at 3070 from C=C bonds) cm-1 890cm-1 (]C=C) 𝛿CH3/CH2 and 1645 , and the peak at (out-of1475 1475”
Invernizzi 等 - 2018 - Mid and Near-Infrared Reflection Spectral Database DOI: 10.1155/2018/7823248
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