What absorbs at 976 cm⁻¹ in an FTIR spectrum?
A band near 976 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 976 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 |
|---|---|---|---|
| Silicon-oxygen (Si-O) | 3 | 3 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Siloxane (Si-O-Si) | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 2 | 2 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Protein | 1 | 1 | 1.0 |
| Silicon silicon | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Ester | 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 |
|---|---|---|---|
| chitosan | 976, 1650, 1655 | Alkyl C-H | 2 |
| Chitosan-Based | 976, 2924, 1743 | Alkyl C-H | 1 |
| PET | 976, 1408, 800 | Alkyl C-H | 1 |
| silk fibroin | 976, 1050, 1511 | Alkyl C-H | 1 |
| CS | 976, 1645, 1720 | Alkyl C-H | 1 |
| collagen | 976, 1408, 1660 | 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 976 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
“The relative intensity of the IR bands at about 1,000cm-1 976cm-1, esterification and assigned to Ala-Gly sequences calculate the yield of because, as expected, the ester 8 Frontiers in Bioengineering and Biotechnology | www.frontiersin.org”
Biagiotti 等 - 2022 - Electrospun Silk Fibroin Scaffolds for Tissue Rege DOI: 10.3389/fbioe.2022.833157 -
Phosphate (PO4) confidence 1.0
“Thus, in order to s-casein solution from 6.8 to 2.0 led to a dramatic establish the actual amplitude and position of the reduction of dianionic symmetric stretching peak pre976cm(cid:1)1 phosphate peak, a curve fitting in the dianionic sent”
Fernandez 等 - 2003 - An FTIR spectroscopy study of the interaction betw DOI: 10.1016/S0958-6946(03)00115-8 -
Acetate confidence 1.0
“Among the more intense bands, we observe in the IR SE spectra the characteristic bands corresponding to the vibration modes of the trans C-O stretch (~976 cm-1), the ester C-C, C-O”
Laskarakis 等 - 2004 - A Spectroscopic Ellipsometry study of PET membrane DOI: 10.1002/masy.200450109 -
Alkyl C-H confidence 1.0
“cm-1 The bands at 975.9, 889.1 and 858.2 are present in both AEMs and are cm-1 associated with the C-H presence [34,44,45].”
Barros 等 - 2020 - A three-stage chemical cleaning of ion-exchange me DOI: 10.1016/j.desal.2020.114628 -
Hydroxyl (O-H) confidence 1.0
“(d) Espectro de absorção na região do infravermelho da vermiculita expandida lavada com H 2O cm-1 em 1651,1 é gerada pela deformação angular O-H da água, e Para verificar uma alteração nas propriedades físicas da cm-1 a banda intensa em 976”
Beluco 等 - 2023 - CHARACTERIZATION OF SOLID RESIDUES THROUGH THERMAL DOI: 10.21577/0100-4042.20230007 -
Alkene (C=C) confidence 1.0
“The wavenumbers at 973 and 976 cm-1 can be assigned to secondary oxidation These results suggest that CBLO produced more trans double bonds and secondary oxiproducts, such as aldehydes or ketones, supporting isolated trans-double bonds [49]”
Chitosan-Based Anti-Oxidation Delivery Nano-Platform: Applications in the Encapsulation of DHA-Enriched Fish Oil DOI: 10.3390/md19080470 -
Acetate confidence 1.0
“C-O-C =O Esters in tannins 990 C-O stretch 976 C =C”
Dickinson 和 High - 2022 - The use of infrared spectroscopy and chemometrics DOI: 10.1186/s40494-022-00690-w -
Alkyl C-H confidence 1.0
“cm-1 The peaks at 976, 834, and 720 are corresponding to (a) the stretching vibration of the -CH group and the bending 2 vibrations of C-H of the aromatic ring [70].”
Radiation Synthesis of Edible Coating Films of Nanocurcumin Based on Carboxymethyl Chitosan/Polyvinyl Alcohol to Extend the Shelf Life of Sweet Orange "Valencia" DOI: 10.1007/s10924-023-02854-6
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