What absorbs at 612 cm⁻¹ in an FTIR spectrum?
A band near 612 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 612 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 | 6 | 6 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| Alkyl C-H | 1 | 1 | 1.0 |
| Silicon silicon | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| C-O single bond | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| S s | 1 | 1 | 1.0 |
| C-S single bond | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| Sulfonyl | 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 |
|---|---|---|---|
| silica | 612, 1100, 1080 | Silicon (Si), Alkyl C-H | 1 |
| CaCO3 | 612, 1141, 712 | Alkyl C-H, Silicon (Si) | 1 |
| alumina | 612, 460, 1000 | Metal oxygen, Alkyl C-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 612 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
-
Sulfonyl confidence 1.0
“The FTIR results for all SRHCs further proved the 611 cm-1 presence of -SO 3H group on the catalysts by the appearance of peak at 1035 which 612 corresponded to O=S=O stretching of -SO 3H group.”
Balan 等 - 2021 - Esterification of residual palm oil using solid ac DOI: 10.1016/j.jtice.2012.07.001. -
Silicon (Si) confidence 1.0
“at wavenumbers of 612 668 and 951 cm-1 C max, of the In accumulation, the maximum capacitance, The peak at 612 is assigned to the characteristic vifilm can be obtained directly, and the dielectric constant of bration mode of Si (100) substr”
Fu 等 - 2012 - Structural, optical and electrical properties of c DOI: 10.1007/s00339-011-6713-5 -
Metal oxygen confidence 1.0
“1036 1386 1630 2922 and 3450 cm-1 The absorption band at 460 has appeared due to the Ga-O cm-1.49,50 stretching mode and due to Mg-O stretching mode at 612 0.5mol%Cr3+,2mol%Si4+ Figure3.”
Mondal 和 Manam - 2017 - Structural and Luminescent Properties of Si4+ Co-D DOI: 10.1149/2.0021708jss -
Metal oxygen confidence 1.0
“cm-1 and 612.36 the strong band around 612 is characteristic of the aurivillius family, it may be assigned to the vibrations of nb-o bonds.”
Structure and Dielectric Properties of V and Y Disorder Doped SrBi2Nb2O9 Ceramics DOI: 10.24425/amm.2022.141073 -
confidence 1.0
“The IR spectra show broad transmission bands centered at cm-1 bands centered at 550 and 612 typical for Ni-O stretching vibrations [27].”
Effect of Modified Alumina Support on the Performance of Ni-Based Catalysts for CO2 Reforming of Methane DOI: 10.3390/catal12091066 -
Sulfate (SO4) confidence 1.0
“in winter and summer are shown in In the two study attributed to the increase in both fossil fuels and biomass cm-1and period, the absorption bands between 612 and 615 burning, which was from the high energy demands by cm-1was attributed to”
Askar 等 - 2022 - Chemical Composition, Optical Properties and Sourc DOI: 10.3389/fenvs.2022.929449 -
C-S single bond confidence 1.0
“cm-1), cm-1) The sharp and intense diffraction peak observed around and 2836 C-S (741, 709, 670, 638 and 612 cm-1) 2q = 15° for crystalline GeS 2, Figure 7a, (referred to and S-S (473 vibration groups.”
De Salvi 等 - 2015 - New Flexible and Transparent Solution-Based German DOI: 10.5935/0103-5053.20150065 -
Metal oxygen confidence 1.0
“The new peaks at 612 and cm(cid:16)1 were associated with the metal-oxygen bonds 464 (Gd-O and Gd-O-Ga) vibrations.”
Dong 等 - 2012 - Preparation and properties of Nd,YbGGG polycrysta DOI: 10.1007/s40145-012-0030-0
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