What absorbs at 946 cm⁻¹ in an FTIR spectrum?
A band near 946 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 946 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 |
|---|---|---|---|
| Metal oxygen | 3 | 2 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Phosphate (PO4) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicate | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 0 | 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 |
|---|---|---|---|
| polymer | 946, 1718, 1722 | 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 946 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
-
Silicate confidence 1.0
“Peak present at 483 and 946cm-1 563cm-1 vibrational mode is present at in Ca2Y2Si2O9 silicate in Ca2Y2Si2O9 and Sr2Y2Si2O9 phosphor is due to the SiO4”
Down-conversion characteristics of Eu3+ doped M2Y2Si2O9 (M = Ba, Ca, Mg and Sr) nanomaterials for innovative solar panels DOI: 10.1016/j.pnsc.2019.07.003 -
Metal oxygen confidence 1.0
“As the absorption edge depends on the oxygen and also contain asymmetric stretching vibrations units.(29,32) network,(38) bond strength in the glass of Bi-O bonds in [BiO 3] pyramidal The the obtained cm-1 cm-1 absorption bands at ~946 and”
Synthesis, thermal and spectroscopic characterization of lithium bismuth borate glasses containing mixed transition metal ions DOI: 10.13036/17533562.57.3.018 -
Phosphate (PO4) confidence 1.0
“In addition, the stretching vibration peaks of P-O were at 1026 cm-1, 946 cm-1 and 920 cm-1;”
-Amino Phosphonic Acid as the Oxidized Ore Collector: Flexible Intra-Molecular Proton Transfer Providing an Improved Flotation Efficiency DOI: 10.3390/min12080918 -
C c single bond confidence 1.0
“In addition, it showed C-H bending cm-1, cm-1, vibrations at 1467 C-O-C (ether) stretching vibrations at 1280 and C-C (ethyl) u cm-1 stretching vibrations at 946 (Frydrych et al.”
Physical properties and solubility studies of Nifedipine-PEG 1450/HPMCAS-HF solid dispersions DOI: 10.1039/C5PY01136A -
Alkene (C=C) confidence 1.0
“[BBSQ-Cu2+], showed a peak at 671.3481, assigned to and Fe3+, Cu2+, Hg2+, and the metal chelator ethylene diamine tetBBSQ-Hg2+ system showed a peak at 945.6797, assigned to aer raacetic acid (EDTA) was added to the system BBSQ OH- [BBSQ-Hg”
NIR squaraine dyes for dual colorimetric and fluorescent determination of Fe3+, Cu2+, and Hg2+ ions DOI: 10.1039/d3ra02419a -
Water (H2O) confidence 1.0
“The bands located at 946 and water molecules represented by peaks at around 3440 and cm(cid:3)1”
Silver-controlled evolution of morphological, structural, and optical properties of three-dimensional hierarchical WO3 structures synthesized from hydrothermal method DOI: 10.1016/j.jallcom.2017.11.095 -
Metal oxygen confidence 1.0
“the carbonyl oxygen acts as the Lewis base and the proton of the hydroxyl group is the Lewis cm-1 cm-1 The peaks observed at 946 and 1037 are from the Al-O and Al-OH stretching and bending vibraal.43 tions.”
Pletincx 等 - 2017 - In Situ Characterization of the Initial Effect of DOI: 10.1038/srep45123 -
confidence 0.7
“Text states tiny peaks around 946 cm-1 are IR characterization for MC.”
Substantial Proton Ion Conduction in Methylcellulose/Pectin/Ammonium Chloride Based Solid Nanocomposite Polymer Electrolytes: Effect of ZnO Nanofiller DOI: 10.3390/membranes12070706
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