What absorbs at 711 cm⁻¹ in an FTIR spectrum?
A band near 711 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 711 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 |
|---|---|---|---|
| Carbonate | 7 | 6 | 1.0 |
| Methacrylate | 2 | 2 | 1.0 |
| C-O single bond | 2 | 2 | 1.0 |
| Acetate | 2 | 2 | 1.0 |
| Alkyl C-H | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Nitrogen heterocycle | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Borate | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Phosphorus | 1 | 1 | 1.0 |
| Phosphate (PO4) | 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 | 711, 1650, 1655 | Acetate, Methacrylate, C-O single bond | 1 |
| chitin | 711, 1650, 1655 | Methacrylate, Acetate, C-O single bond | 1 |
| hematite | 711, 1030, 469 | C-O single bond | 1 |
| goethite | 711, 1470, 696 | 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 711 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
-
Phosphate (PO4) confidence 1.0
“A peak at 1,071 calcite has a can be aspeak at 711 because the single peak 4 cm-1) m m signed to the carbonate would be very narrow (bandwidth 5-6 1-phosphate vibrations, and the and a more 3 cm-1 m intensity indicates that the apatite is s”
Awonusi 等 - 2007 - Carbonate assignment and calibration in the raman DOI: 10.1007/s00223-007-9034-0 -
Metal oxygen confidence 1.0
“LLM confirmed rule peak-group candidate”
Synthesis of Citrus Limon mediated SnO2-WO3 nanocomposite: Applications to photocatalytic activity and electrochemical sensor DOI: 10.1016/j.jece.2020.104500 -
C-O single bond confidence 1.0
“catedthat ferricironislinkedto OHligands.The shiftintheFe 2p 3/ aFeOOH Inatotalof7samplesoftype3ironore,the(d-OH)bandofgoepeak binding energy (711.2eV) corresponds to species 2 905cm(cid:3)1, c-OH thite varies from 892 to (Fig.”
Spectroscopic characterization of iron ores formed in different geological environments using FTIR, XPS, Mössbauer spectroscopy and thermoanalyses DOI: 10.1016/j.saa.2014.10.090 -
Ring structure confidence 1.0
“Among them, 711, 871 and 872 cm-1 indicate -NH out of plane bending for chitosan and ring stretching (Fig.”
Sudatta 等 - 2020 - Extraction, characterization and antimicrobial act DOI: 10.1016/j.ijbiomac.2020.06.291 -
C-S single bond confidence 1.0
“And another peak at trile This work was financially supported by the China Postdoccm-1 about 711 is ascribed to the C-S stretching vibration of the Science Foundation (20100480592), the Special Grant from toral DMSO.”
Tan 和 Wan - 2011 - Structural changes in thermal-induced polyacryloni DOI: 10.1016/j.colsurfa.2011.10.014 -
Alkyl C-H confidence 1.0
“LLM confirmed rule peak-group candidate”
Varma 和 Vasudevan - 2020 - Extraction, Characterization, and Antimicrobial Ac DOI: 10.1021/acsomega.0c01903 -
Borate confidence 1.0
“Y3+ 711cm-1 a blue shift with the increase of ion molar fraction in and origin from the B-O bond bending vibrations of 0.053+ (Y x,Gd 0.95-x)BO 3:Eu compounds.”
Zhang 等 - 2008 - Infrared spectra and luminescence properties of (Y DOI: 10.1016/j.jallcom.2007.01.010 -
Carbonate confidence 1.0
“Absorption bands at 2512, 1796, 1395 and 711 cm-1 are assigned to calcite CaCO3.”
Akhtar 等 - 2022 - Advanced Treatment of Direct Dye Wastewater Using DOI: 10.3390/separations9120425
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