What absorbs at 995 cm⁻¹ in an FTIR spectrum?
A band near 995 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 995 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 |
|---|---|---|---|
| Hydroxyl (O-H) | 5 | 5 | 1.0 |
| Methoxy (OCH3) | 5 | 5 | 1.0 |
| Methacrylate | 5 | 5 | 1.0 |
| C-O single bond | 5 | 5 | 1.0 |
| Acetate | 5 | 5 | 1.0 |
| Carbohydrate | 5 | 5 | 1.0 |
| Alkyl C-H | 3 | 3 | 1.0 |
| Phosphate (PO4) | 3 | 2 | 1.0 |
| Borate | 2 | 2 | 1.0 |
| Phosphorus | 2 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Phospholipid | 1 | 1 | 1.0 |
| Alkene (C=C) | 1 | 1 | 1.0 |
| Sulfate (SO4) | 1 | 1 | 1.0 |
| Amide | 1 | 1 | 1.0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Silicon (Si) | 1 | 1 | 1.0 |
| Hydrogen bond | 1 | 1 | 1.0 |
| N h | 1 | 0 | 1.0 |
| Ring structure | 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 |
|---|---|---|---|
| starch | 995, 1650, 1540 | Hydroxyl (O-H), Methacrylate, 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 995 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
-
Hydrogen bond confidence 1.0
“Polymers2022,14,1086 13of17 cm-1 of starch, respectively, and the band at 995 was related to the intramolecular hydrogen bonds of the hydroxyl group at C-6 [64].”
Dual Modification of Sago Starch via Heat Moisture Treatment and Octenyl Succinylation to Improve Starch Hydrophobicity DOI: 10.3390/polym14061086 -
Acetate confidence 1.0
“1154 C-O stretching (of succinite) 995 ± 15 982 996 992”
Differentiation between copal and amber by their structure and thermal behaviour DOI: 10.1007/s10973-023-12333-8 -
Carbohydrate confidence 1.0
“diffractominor new peak appeared at approximately = 13° in the cm-1 whereas the bands at 995 and 1047 were related to the amounts grams of GA-RS complexes, while gelatinized starch did not exhibit this of ordered regions (Lopez-Rubio, Flana”
Physicochemical interactions between rice starch and different polyphenols and structural characterization of their complexes DOI: 10.1016/j.lwt.2020.109227 -
confidence 1.0
“The band appeared at 995 is min-1) nitrogen atmosphere (100 mL in the temperfor the S-O stretching vibrations, this S-O moiety was (cid:3)C ature range from 30 to 1200 at a heating rate of from the BMIM MeSO IL.”
Lakshmanamoorthy 和 Manivannan - 2022 - Ionic liquids assist synthesis of AgAgX (X = Cl, DOI: 10.1007/s10854-021-06774-w -
Silicon (Si) confidence 1.0
“Bands at 905 and 995 cm-1 are assigned to Si-O-Ca stretching vibrations of C2S, and this phase gives J.Funct.”
The Application of 29Si NMR Spectroscopy to the Analysis of Calcium Silicate-Based Cement using Biodentine™ as an Example DOI: 10.3390/jfb10020025 -
Alkyl C-H confidence 1.0
“cm)1, 1095 and 1199 while CH C shows four specific peaks at 995,”
Vodnar 等 - 2010 - Morphology, FTIR fingerprint and survivability of DOI: 10.1111/j.1365-2621.2010.02406.x -
Carbohydrate confidence 1.0
“The same PC was also used to run Pike TemPRO spectrum of native starch shows peaks at 995 and 1022 software, which was used to control the heated ATR crystal and”
Warren 等 - 2013 - Infrared Spectroscopy with Heated Attenuated Total DOI: 10.1021/ac303552s -
Silanol (Si-OH) confidence 1.0
“suggested that the Si-OH bands located at 995 cm-1 cm-1, and 697 correabsorption peaks at 601”
Yuan 等 - 2015 - Hydrophobic effect of silica functionalized with s DOI: 10.1007/s12039-015-0965-0
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