What absorbs at 1005 cm⁻¹ in an FTIR spectrum?
A band near 1005 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 1005 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 |
|---|---|---|---|
| Alkyl C-H | 5 | 5 | 1.0 |
| Methoxy (OCH3) | 4 | 4 | 1.0 |
| Methacrylate | 4 | 4 | 1.0 |
| Acetate | 4 | 4 | 1.0 |
| Hydroxyl (O-H) | 4 | 3 | 1.0 |
| Silicon-oxygen (Si-O) | 4 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| Silicon (Si) | 3 | 2 | 1.0 |
| Amide | 2 | 2 | 1.0 |
| Metal oxygen | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Methyl | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Thiol | 1 | 1 | 1.0 |
| Secondary amine | 1 | 1 | 1.0 |
| C n single bond | 1 | 1 | 1.0 |
| Carboxyl (COOH) | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 0 | 1.0 |
Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.
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 1005 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
-
Carboxyl (COOH) confidence 1.0
“Lastly, a peak at 1005 corresponding to the presence of presence of COO-), followed by another peak at 1020 cm-1, which represents the presence PO groups, was observed, which indicates the presence of carbonated hydroxyapatite in 4 of PO4 g”
Remineralization Potential of Three Restorative Glass Ionomer Cements: An In Vitro Study DOI: 10.3390/jcm12062434 -
confidence 1.0
“As we notice from Figure 7, the decrease in the intensity of the main absorption band related to νas of Si-O-T (at 1005 cm-1) in the case of the SF-Cu2+ mix is further evidence of the geopolymerization retardation effect of copper ions.”
Ahmed 等 - 2023 - Immobilization Approach as a Creative Strategy to DOI: 10.3390/polym15071797 -
Acetate confidence 1.0
“At 1005 was a C-O stretch of carbohydrate anhydrides [36].”
A Soluble Humic Substance for the Simultaneous Removal of Cadmium and Arsenic from Contaminated Soils DOI: 10.3390/ijerph16244999 -
Amide confidence 1.0
“The band at 860 cm-1 was assigned to C-N stretching modes of cm-1 UiO-66-10BA and UiO-66-60BA samples contained a peak at 1005 associated with”
Butova 等 - 2023 - In Situ FTIR Spectroscopy for Scanning Accessible DOI: 10.3390/nano13101675 -
Hydroxyl (O-H) confidence 1.0
“C-C-O stretching 1234 C-O stretching 1056 O-H stretching 1005”
Quantification of the Geranium Essential Oil, Palmarosa Essential Oil and Phenylethyl Alcohol in Rosa damascena Essential Oil Using ATR-FTIR Spectroscopy Combined with Chemometrics DOI: 10.3390/foods10081848 -
Thiol confidence 1.0
“It can be known from relative articles (Bernard et al., 2017) figure that, the characteristic peak of M-S-H in the appears at 1005.4cm-1.”
Chen 等 - 2021 - Study on Metakaolin Impact on Concrete Performance DOI: 10.3389/fmats.2021.788079 -
Hydroxyl (O-H) confidence 1.0
“As for the OH stretching bands, they enable a disfor the most intense peak and at ∼1005cm-1 crimination of the serpentine species from each other.”
Fritsch 等 - 2021 - Structural, textural, and chemical controls on the DOI: 10.5194/ejm-33-447-2021 -
Acetate confidence 1.0
“Furthermore, the absorption bands which appeared at 1090, 1050 and 1005 cm-1 can be assigned to the asymmetric stretching vibration of C-O-C aliphatic ether function [15].”
Synthesis Characterization and Highly Protective Efficiency of Tetraglycidyloxy Pentanal Epoxy Prepolymer as a Potential Corrosion Inhibitor for Mild Steel in 1 M HCl Medium DOI: 10.3390/polym14153100
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