What absorbs at 1401 cm⁻¹ in an FTIR spectrum?
A band near 1401 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 1401 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 |
|---|---|---|---|
| C-O single bond | 5 | 4 | 1.0 |
| Hydroxyl (O-H) | 4 | 4 | 1.0 |
| Alkyl C-H | 4 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 2 | 1.0 |
| Methoxy (OCH3) | 3 | 2 | 1.0 |
| Methacrylate | 3 | 2 | 1.0 |
| Acetate | 3 | 2 | 1.0 |
| N h | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| Ammonium | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| Phospholipid | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Lipid | 1 | 1 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 0.8 |
| Amino acid | 1 | 0 | 1.0 |
| Carbonate | 1 | 0 | 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 |
|---|---|---|---|
| ZnO | 1401, 1400, 3430 | Hydroxyl (O-H), Alkyl C-H, C-O single bond | 1 |
| Polyaniline | 1401, 1565, 1570 | Alkyl C-H | 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 1401 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
-
Ester confidence 1.0
“octadecenoic acid (Z), methyl ester and 9-octadecenoic acid, 1,2,3-proTheintenseandstrongpeaks1401,1395and1409cm(cid:3)1inC.officinalis, panetriyl ester (E,E,E), respectively.”
El-Sayed 和 Ismail - 2022 - Physico-chemodiversity variation between the most DOI: 10.1016/j.heliyon.2022.e12457 -
C-O single bond confidence 1.0
“The symmetric and antisymmetric stretching modes of alcoholic -C-OH vibrations are obtained at 1401 2864 and 2902 cm-1”
Synthesis and characterization of cobalt ferrite nanoparticles for hyperthermia treatment application DOI: 10.1063/1.5052096 -
C c single bond confidence 1.0
“thesamepHvalue,itisclear thatthis discrepancyiscaused to the C C stretching vibrations of the benzene ring and quinonering,respectively.Aprominentpeakat1401cm(cid:2)1 by the scan rate.”
Polyaniline with Two Types of Functional Groups: Preparation and Characteristics DOI: 10.1002/macp.200400408 -
Carbohydrate confidence 1.0
“The peak of 1401 cm-1 represents hemicellulose.”
Evaluation of OKRA (Abelmoschus esculentus) Macromolecular Solution for Enhanced Oil Recovery in Kazakhstan Carbonate Reservoir DOI: 10.3390/en15186827 -
Acetate confidence 1.0
“The presence of this carbon resulted in the emergence of absorption bands at 1123, 1401 cm-1, and 20,968 related to C-O, C-H and C-OH, respectively.”
Rapid Bio-Assisted Synthesis and Magnetic Behavior of Zinc Oxide/Carbon Nanoparticles DOI: 10.3390/cryst13071081 -
confidence 1.0
“Explicit assignment: '1401 ... attributed to C-O'”
Li 等 - 2020 - Magnetic responsive Thermomyces lanuginosus lipase DOI: 10.1016/j.mtcomm.2020.101197 -
C c single bond confidence 1.0
“Physicochemical property % age content ± SD stretching and C=C stretching at 1637 cm-1 and C-C Moisture content 8.5 ± 0.08 stretching at 1401 cm-1 have confirmed the presence of Total ash 10.35±0.14”
Nabi 等 - 2023 - ANTIOXIDANT AND ANTI-INFLAMMATORY POTENTIAL OF DAU DOI: 10.36899/JAPS.2023.1.0612 -
Hydroxyl (O-H) confidence 1.0
“Figure 4), displayed broad (cm-1) which is characteristic of hydroxyl groups from stretching peak at around 3551.57 to 3237.44 cm-1, polymeric and dimeric OH stretch and a 1401.49 typical of phenol or tertiary alcohol OH (cm-1) bend [27].”
A Freshwater Streptomyces, Isolated from Tyume River, Produces a Predominantly Extracellular Glycoprotein Bioflocculant DOI: 10.3390/ijms13078679
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a literature-backed analysis — in seconds.