What absorbs at 1247 cm⁻¹ in an FTIR spectrum?
A band near 1247 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 1247 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) | 7 | 7 | 1.0 |
| Methacrylate | 7 | 7 | 1.0 |
| C-O single bond | 7 | 7 | 1.0 |
| Acetate | 7 | 7 | 1.0 |
| Alkyl C-H | 5 | 5 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Ester | 3 | 3 | 1.0 |
| Amide | 3 | 3 | 1.0 |
| Ring structure | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Secondary amine | 2 | 2 | 1.0 |
| Lignin | 2 | 2 | 1.0 |
| Nucleic acid | 2 | 2 | 1.0 |
| Carboxyl (COOH) | 2 | 2 | 1.0 |
| Protein random coil | 1 | 1 | 1.0 |
| Phospholipid | 1 | 1 | 1.0 |
| N h | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Fatty acid | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 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 |
|---|---|---|---|
| Hemicellulose | 1247, 1730, 897 | Methacrylate, Acetate, C-O single bond | 1 |
| AgNPs | 1247, 1232, 1048 | Methacrylate, Acetate, Methoxy (OCH3) | 1 |
| Polysaccharide | 1247, 1637, 1320 | Methacrylate, Acetate, C-O single bond | 1 |
| CMC | 1247, 1423, 1196 | 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 1247 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
-
Acetate confidence 1.0
“composition of the fiber is typified by the stretching band of C-O group at 1247 cm-1 wavenumber is allegedly C=O stretching evidencing the Meanwhile, the peak at 1735.03 existence of hemicelluloses and pectin.”
Ikramullah 等 - 2018 - Hemicellulose and lignin removal on typha fiber by DOI: 10.1088/1757-899X/352/1/012019 -
Sulfate (SO4) confidence 1.0
“Thus, cm-1, absorption bands appear at 1247 which correspond to the vibrations of the sulfate group.”
Kazachenko 等 - 2021 - Food Xanthan Polysaccharide Sulfation Process with DOI: 10.3390/foods10112571 -
Carboxyl (COOH) confidence 1.0
“cm-1 Twin and 1247 The former peak is related to the carboxylic group that could 1730 be present in the fiber as traces of fatty acids present in oils;”
Rubber-Wood Composites from Chemically Modified Olive Husk Powder and Carboxylated Nitrile Butadiene Rubber: Cure Characteristics, Tensile Behavior, and Morphological Studies DOI: 10.1080/02773813.2011.599469 -
Amide confidence 1.0
“LLM confirmed rule peak-group candidate”
The role of topically applied l-ascorbic acid in ex-vivo examination of burn-injured human skin DOI: 10.1016/j.saa.2017.05.055 -
Hydroxyl (O-H) confidence 1.0
“The weak IR bands at 1247, 1110, 1042 and 990 are probably due to overtones, combinations bending modes of different types of surface terminated OH on SnO quantum dots 2 [28].”
Shajira 等 - 2015 - Sunlight assisted photodegradation by tin oxide qu DOI: 10.1016/j.jpcs.2015.09.003 -
Nucleic acid confidence 1.0
“of phosphates is greatly suppressed in comparison with 51 the symmetric one, and differently structured compared to 52 the corresponding RNA and ds-DNA bands (band components are peaked at ~1247 cm-1, ~1233 cm-1 and ~1219 53”
Zucchiatti 等 - 2016 - Contribution of Ribonucleic Acid (RNA) to the Four DOI: 10.1021/acs.analchem.6b02744 -
Acetate confidence 1.0
“The peak which appears at 1247 cm-1 may be due to C-O-H bending vibrations.”
Microwave Accelerated Green Synthesis of Stable Silver Nanoparticles with Eucalyptus globulus Leaf Extract and Their Antibacterial and Antibiofilm Activity on Clinical Isolates DOI: 10.1371/journal.pone.0131178 -
Amide confidence 1.0
“7b), while cm1 cm1 the 1448 (N-C-N asymmetric stretching) and the 1247 peak (C-N stretching, amine) can be linked to the urea byproduct(Piasek Z.”
Azrak 等 - 2021 - Controlled Dispersion and Setting of Cellulose Nan DOI: 10.21203/rs.3.rs-376512/v1
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