What absorbs at 961 cm⁻¹ in an FTIR spectrum?
A band near 961 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 961 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 |
|---|---|---|---|
| Phosphate (PO4) | 7 | 7 | 1.0 |
| Alkyl C-H | 6 | 6 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Bromine | 1 | 1 | 1.0 |
| Carbon bromine | 1 | 1 | 1.0 |
| Chlorine | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Silicon carbon | 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 |
|---|---|---|---|
| polypropylene | 961, 1030, 1600 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| CS | 961, 1645, 1720 | Hydroxyl (O-H), Alkyl C-H | 1 |
| CA | 961, 1045, 1650 | Hydroxyl (O-H), Alkyl C-H | 1 |
| polyethylene | 961, 1737, 1720 | Alkyl C-H, Hydroxyl (O-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 961 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
-
Silicon carbon confidence 1.0
“2 3 3 cm-1, cm-1 cm-1, SiOCH 2CH at 1390 SiOC symmetric stretch at 961 and SiC stretch at 789 are”
Chen 等 - 2007 - Structural characterization and corrosion properti DOI: 10.4028/www.scientific.net/MSF.546-549.1111 -
confidence 1.0
“The MR analysis demonstrated the formation of calcium-MDP salts in the nanolayer cm(cid:3)1 (v1 the areas corresponding to the band at 961 as a response to the chemical interaction between phosphate) were more intense in the dentin in the t”
Oliveira 等 - 2017 - Chemical Interaction Analysis of an Adhesive Conta DOI: 10.2341/16-062-L -
Alkyl C-H confidence 1.0
“The strong peak at 1105 corresponds to C-O-C asymmetric stretching, whereas the stretching vibrations of CH 2-CO presented in the PEO chemical structure are cm-1 attributed to the peaks at 961 and 846 [29].”
Cojocaru 等 - 2022 - Electrospun Nanofibrous Membranes Based on Citric DOI: 10.3390/polym14020294 -
Silicon (Si) confidence 1.0
“The band at 961 can be attributed to a coupling element mapping images of Si, Ca and O of the CSH are shown Si-O-Si, Si-OH 3O-Ca of the vibrations of the and Si(OSi)”
Facile synthesis of novel calcium silicate hydrated-nylon 6/66 nanocomposites by solution mixing method DOI: 10.1039/c8ra07116k -
C-O single bond confidence 1.0
“cm-1 cm-1 exhibits that the peaks of C-OH at 3369 and 1016 of PER and (P=O)-OH at 2686 and 961 cm-1 disappear, and the two new peaks at 1089 and 1045 appear, as shown in Figure 1D.”
He 等 - 2019 - Novel Intumescent Flame Retardant Masterbatch Prep DOI: 10.3390/polym11010050 -
Alkyl C-H confidence 1.0
“The peaks at 961 and 829 corstructures could be obtained from the ratio of intensities of UV cm(cid:1)1 Open C-H responded to the group vibrations.”
l-Alanine capping of ZnO nanorods: increased carrier concentration in ZnO/CuI heterojunction diode DOI: 10.1039/c7ra12385j -
Hydroxyl (O-H) confidence 1.0
“cm-1 tively A steady peak at 1459 reveals the cm-1 medium peaks at 961, 845 and 521 discloses the presence of carbolic acids, alkyl halides with O-H bend, C-Cl stretch and C-Br stretch, respectively.”
Masilamani 等 - 2023 - Characterization, Cytotoxicity and Anti-oxidant St DOI: 10.18502/ajmb.v15i3.12930 -
Alkyl C-H confidence 1.0
“bend was shown at peak 960.89 Other absorption band that was observed in Figure showed CH2 rock cm(cid:0) 1.”
Evaluation of microplastics isolated from sea cucumber A caudina molpadioides in Pulau Langkawi, Malaysia DOI: 10.1016/j.heliyon.2023.e16822
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