What absorbs at 1400 cm⁻¹ in an FTIR spectrum?
A band near 1400 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 1400 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.
Möjliga identifieringar av funktionella grupper
| Funktionell grupp | Stödjande fakta | Citerade källor | Högsta förtroende |
|---|---|---|---|
| Alkyl C-H | 54 | 49 | 1,0 |
| Carboxyl (COOH) | 37 | 33 | 1,0 |
| Methacrylate | 33 | 32 | 1,0 |
| Acetate | 33 | 32 | 1,0 |
| Amide | 28 | 27 | 1,0 |
| C-O single bond | 26 | 26 | 1,0 |
| Methoxy (OCH3) | 26 | 25 | 1,0 |
| Hydroxyl (O-H) | 22 | 19 | 1,0 |
| Carbonate | 17 | 15 | 1,0 |
| N h | 15 | 15 | 1,0 |
| Secondary amine | 11 | 11 | 1,0 |
| Aromatic ring | 10 | 10 | 1,0 |
| Ester | 9 | 9 | 1,0 |
| Carbonyl (C=O) | 8 | 8 | 1,0 |
| C n single bond | 7 | 7 | 1,0 |
| Ketone | 7 | 7 | 1,0 |
| C c single bond | 7 | 7 | 1,0 |
| Methyl | 6 | 5 | 1,0 |
| Amino acid | 6 | 5 | 1,0 |
| Protein | 5 | 5 | 1,0 |
| Boron nitrogen | 5 | 3 | 1,0 |
| Ring structure | 4 | 4 | 1,0 |
| Fatty acid | 4 | 3 | 1,0 |
| Amine primary | 3 | 3 | 1,0 |
| Silicon-oxygen (Si-O) | 3 | 3 | 1,0 |
| Silicate | 3 | 3 | 1,0 |
| Metal oxygen | 3 | 3 | 1,0 |
| Borate | 3 | 3 | 1,0 |
| Fluorine (C-F) | 2 | 2 | 1,0 |
| Phospholipid | 2 | 2 | 1,0 |
| Ammonium | 2 | 2 | 1,0 |
| Bromine | 2 | 2 | 1,0 |
| Water (H2O) | 2 | 2 | 1,0 |
| Silicon (Si) | 2 | 1 | 1,0 |
| Silicon carbon | 2 | 1 | 1,0 |
| Phosphate (PO4) | 1 | 1 | 1,0 |
| C=n | 1 | 1 | 1,0 |
| Bronsted acid site | 1 | 1 | 1,0 |
| Hydrogen bond | 1 | 1 | 1,0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1,0 |
| Carbohydrate | 1 | 1 | 1,0 |
| Carbon bromine | 1 | 1 | 1,0 |
| Carbon dioxide | 1 | 1 | 1,0 |
| N eq o | 1 | 1 | 0,7 |
| Lipid | 1 | 0 | 1,0 |
Rankingen speglar ackumulerade litteraturbevis, inte en enda auktoritativ regel. Bekräfta alltid mot din provkontext.
Possible materials
| Material | Stödjande toppar | Overlapping groups | Citerade källor |
|---|---|---|---|
| ZnO | 1400, 3430, 2353 | Alkyl C-H, Acetate, Methacrylate | 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 1400 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.
Litteratur bakom dessa identifieringar
-
Carboxyl (COOH) förtroende 1,0
“The two principal absorption peaks are observed between 1400 and corresponding to the symmetric and asymmetric stretching of the carboxyl group (C=O).”
Mn doped ZnO nanostructured thin films prepared by ultrasonic spray pyrolysis method DOI: 10.1016/j.spmi.2012.06.023 -
Carboxyl (COOH) förtroende 1,0
“1400 for symmetric stretching cm-1 vibration of deprotonated carboxylic acid groups;”
Bakr 等 - 2021 - Predictive performance of auto-aerated immobilized DOI: 10.1016/j.eti.2020.101327 -
Boron nitrogen förtroende 1,0
“LLM confirmed rule peak-group candidate”
Bejarano 等 - 2006 - Deposition of B4CBCNc-BN multilayered thin films DOI: 10.1016/j.tsf.2005.08.192 -
Carboxyl (COOH) förtroende 1,0
“(1250cm-1),C\\Cstretchofaromaticcompounds(1400cm-1),N\\H cm-1) and carboxylic acids bends due to primary amines (1650 2.6.”
A rapid method for fungal assisted algal flocculation: Critical parameters & mechanism insights DOI: 10.1016/j.algal.2016.10.022 -
Boron nitrogen förtroende 1,0
“cm-1 cm-1 Assuming that the in-plane h-BN peak at 1400 and the c-BN TO-peak at 1100 have similar absorption coefficients, the fraction of the cubic phase in the films can be derived by fitting each peaks to °C, a Lorenzian-type function [6]”
Cubic and hexagonal boron-nitride (c-BN/h-BN) thin films deposited in situ by r.f. magnetron sputtering DOI: 10.1002/pssb.200461776 -
Water (H2O) förtroende 1,0
“The peak recorded at cm(cid:1)1 in the RM and RM samples could be ficial absorbed water, with the temperature of the peak 1400 nt a Vol.”
Castaldi 等 - 2008 - XRD, FTIR, and thermal analysis of bauxite ore-pro DOI: 10.1346/CCMN.2008.0560407 -
förtroende 1,0
“II band at 1400 indicates the generation of amino acids β-Carotene confirming Bioaccessibility of in In Vitro Digestion.”
Remodeling of β‑Carotene-Encapsulated Protein-Stabilized Nanoparticles during Gastrointestinal Digestion In Vitro and in Mice DOI: 10.1021/acs.jafc.0c05322 -
Acetate förtroende 1,0
“The absorption peak at 1400 was assigned cell volume, bond lengths and bond angles of to the stretching of the C-O bond.”
Influence of Ho3+ substitution on structural and magnetic properties of Mg–Mn ferrites DOI: 10.1007/s10854-021-05547-9
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