What absorbs at 924 cm⁻¹ in an FTIR spectrum?
A band near 924 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 924 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 |
|---|---|---|---|
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| Methacrylate | 5 | 5 | 1.0 |
| C-O single bond | 5 | 5 | 1.0 |
| Acetate | 5 | 5 | 1.0 |
| Alkyl C-H | 4 | 4 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Oxalate | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Nucleic acid | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Amide | 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 | 924, 1650, 1655 | Acetate, Methacrylate, C-O single bond | 2 |
| silver nanoparticles | 924, 1636, 1631 | Methacrylate, Acetate, C-O single bond | 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 924 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
-
Hydroxyl (O-H) confidence 1.0
“cmK1 cmK1 g centered around 970 can be assigned to OH, the out-ofto an Evans phenomenon is less obvious, but it 1440 plane bending of the O-H bond, while the sharp peaks at 924, cannot be entirely excluded.”
Hansen 等 - 2006 - Intramolecular hydrogen bonding. Spectroscopic and DOI: 10.1016/j.molstruc.2005.10.051 -
Secondary amine confidence 1.0
“N-H presence of the sharp peak at 3,422.13 stands for cm-1 stretch (primary, secondary amines, amides), 2,924.12 cm-1 H-C=O: C-H stretch (aldehydes), 2,851.76 stands cm-1 C-C for OH (intramolecular bonds), 1,631.41 for cm-1 (in-ring) stretc”
Marimuthu 等 - 2012 - Lousicidal activity of synthesized silver nanopart DOI: 10.1007/s00436-011-2667-y -
Acetate confidence 1.0
“The increasein prominence of Peak bands between 924 and 925 were due to the contribution C-O, C-O-H C-O-C the pores with increase in glycerol content could be due to hydrophobic of saccharide structure.”
Alimi 等 - 2022 - Microstructural and physicochemical properties of DOI: 10.1016/j.heliyon.2022.e09148 -
Amide confidence 1.0
“In C-O, C-C, C-H (genipin) 3089, 1441, 721 2320 cm-1 addition, the C-N stretching of amide III at 1233 shifted to 1260 C-C, C-O, C-N (absorption 2884, 2683, 1952 1955, 1334, 1090, 924 cm-1 cm-1, after crosslinking with genipin, while the pe”
Delgadillo-Armendariz 等 - 2014 - INTERACTIONS OF CHITOSANGENIPIN HYDROGELS DURING DOI: 10.5935/0100-4042.20140243 -
Acetate confidence 1.0
“2 cm-1) -OH scissoring bends at 1454 and 1415 and (ii) contribution to related vibrations cm-1 cm-1 in 3000-3500 (O-H stretches) and in 1150-800 (C-O stretches), where the presence of glycerol is usually accompanied by characteristic asymme”
Incorporation of Natural Blueberry, Red Grapes and Parsley Extract By-Products into the Production of Chitosan Edible Films DOI: 10.3390/polym13193388 -
confidence 1.0
“También es posible observar bandas de un 2533, 1808, 1446, 870, and 716 cm-1, although bands from an compuesto de silicio no cristalino a 1110 (Si-O) y 924 cm-1 (C-O) organic molecule at 2945, 2889 (C-H), and 1034 cm-1 can be seen in and (S”
Fragoso 等 - 2010 - Characterization of the CaCO3 biomineral in corall DOI: 10.7773/cm.v36i1.1606 -
Nucleic acid confidence 1.0
“cm-1 cm-1 of the bands at about 924 and 996 indicate the This indicates the possibility of some biochemical changes presence of changes on the level of DNA and RNA synthesis, occurring during cell culture associated only with the culture re”
Lach 等 - 2021 - First Identification of the Effects of Low Frequen DOI: 10.4103/jmp.jmp_57_21 -
Alkyl C-H confidence 1.0
“The intensity of the signal for C-H out-of-plane bending (924 cm-1) decreased gradually upon increasing the curing temperature;”
Lin 等 - 2017 - Coumarinand Carboxyl-Functionalized Supramolecul DOI: 10.3390/polym9040146
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