What absorbs at 712 cm⁻¹ in an FTIR spectrum?
A band near 712 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 712 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 | 17 | 17 | 1.0 |
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| C-O single bond | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Carbohydrate | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| N-O bond | 1 | 1 | 1.0 |
| Protein | 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 |
|---|---|---|---|
| CaCO3 | 712, 1141, 1444 | Carbonate, C-O single bond | 1 |
| calcium carbonate | 712, 3232, 2954 | Carbonate, C-O single bond, Methoxy (OCH3) | 1 |
| calcite | 712, 2850, 2864 | Carbonate, Methacrylate, Methoxy (OCH3) | 1 |
| collagen | 712, 1408, 1660 | Methacrylate, Methoxy (OCH3), C-O single bond | 1 |
| calcium phosphate | 712, 1070, 1149 | C-O single bond, Carbonate, Methoxy (OCH3) | 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 712 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
-
Protein confidence 1.0
“ATRtypical peak shift to 872 and the peak at 712 The ton with Cd, Cr, Pb, Ni, and Zn revealed qualitative peaks in correspondence to proteins and chitin appeared less FTIR profile modifications: the shift of the peak from 859 to cm-1 cm-1.”
Fast non-destructive assessment of heavy metal presence by ATR–FTIR analysis of crayfish exoskeleton DOI: 10.1007/s11356-020-08405-z -
confidence 1.0
“cm-1 Another deformation band found at 712 can be attributed to the O-C-O grouping from the 32CO ion, which is the allotropic form vaterite [26].”
The Comparative Study of the State of Conservation of Two Medieval Documents on Parchment from Different Historical Periods DOI: 10.3390/ma13214766 -
N-O bond confidence 1.0
“It is noteworthy that no peak at 712 cm-1 attributable cm-1.”
Evidence for Mild Diagenesis in Archaeological Human Bones from the Fewet Necropolis (SW Libya): New Insights and Implications from ATR–FTIR Spectroscopy DOI: 10.3390/app13020687 -
Aromatic ring confidence 1.0
“LLM confirmed rule peak-group candidate”
Chen 等 - 2019 - In Vitro Toxicity Study of a Porous Iron(III) Meta DOI: 10.3390/molecules24071211 -
Carbonate confidence 1.0
“The 3 spectrum of the CaCO produced at 20 °C (FIGURE 3 (a)) shows the absorption bands at approximately of 712, 871, 3 cm-1, 1089, 1389 and 1799 corresponding to calcite.”
Chong 等 - 2014 - Polymorphs Calcium Carbonate on Temperature Reacti DOI: 10.1063/1.4895169 -
Carbonate confidence 1.0
“The high content of carbonate ions (decm-1) spite the absence of the v vibration at 712 The diagnosis of bladder stones is immediately con4 suggests that the sample does not contain (or very firmed in our study by the concentric arrangement”
SEM-EDX micro-analysis and FTIR infrared microscopy by ATR of a bladder stone from the IIIth millennium BC from the B1S passage-grave of the necropolis in Chenon (Charente, France) DOI: 10.5802/crchim.143 -
Acetate confidence 1.0
“in North West European recipes [22, 23] was identified recipes from the seventeenth centuries such as the ones by the strong peaks observed around ~ 1400, 872 and from De Mayerne manuscript, indicate that manganesecm-1 712 (C-O stretching o”
Cortea 等 - 2020 - Uncovering hidden jewels an investigation of the DOI: 10.1186/s40494-020-00401-3 -
Carbonate confidence 1.0
“In the spectrum of calcite (Figure 5e), the characteristic peaks at 872 and 712 cm-1 are clearly distinguishable, while that at 1415 cm-1 (also characteristic of calcite) is covered by the large band”
D'Elia 等 - 2007 - Evaluation of possible contamination sources in th DOI: 10.1017/S0033822200042120
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