What absorbs at 998 cm⁻¹ in an FTIR spectrum?
A band near 998 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 998 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.
Possibili assegnazioni di gruppi funzionali
| Gruppo funzionale | Fatti di supporto | Fonti citate | Affidabilità massima |
|---|---|---|---|
| Alkyl C-H | 4 | 4 | 1,0 |
| Hydroxyl (O-H) | 4 | 4 | 1,0 |
| Silicon-oxygen (Si-O) | 4 | 4 | 1,0 |
| Amide | 3 | 3 | 1,0 |
| Silicon (Si) | 3 | 3 | 1,0 |
| Methacrylate | 2 | 2 | 1,0 |
| Acetate | 2 | 2 | 1,0 |
| Secondary amine | 2 | 2 | 1,0 |
| C n single bond | 2 | 2 | 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 |
| Hydrogen bond | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Silanol (Si-OH) | 1 | 1 | 1,0 |
| Ring structure | 1 | 1 | 1,0 |
La classifica riflette le prove bibliografiche accumulate, non una singola regola autorevole. Conferma sempre nel contesto del tuo campione.
Possible materials
| Materiale | Picchi di supporto | Overlapping groups | Fonti citate |
|---|---|---|---|
| polypropylene | 998, 1030, 1600 | Alkyl C-H, Hydroxyl (O-H), Amide | 1 |
| TiO2 | 998, 1700, 1093 | Hydroxyl (O-H), Alkyl C-H | 1 |
| ZnO | 998, 1400, 3430 | Hydroxyl (O-H), Alkyl C-H, Amide | 1 |
| rGO | 998, 2358, 2930 | Hydroxyl (O-H), Alkyl C-H, Amide | 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 998 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.
Letteratura dietro queste assegnazioni
-
Alkyl C-H affidabilità 1,0
“The calculated using peaks of 998 and 973 cm1 C-CH involves the CH rocking, the stretching, the CH bending and the CH twisting -band at 998 3”
Chen 等 - 2015 - The spatial correlation between crystalline and am DOI: 10.1007/s10118-015-1613-3 -
Ring structure affidabilità 1,0
“Fourier transform infra-red (FTIR) analysis cm-1 confirm 3:Ce3+ cm-1 The FTIR spectra of CaSiO phosphor was recorded in the range 400 - 4000 to the functional groups presentintheobtainedsamples,Fig.2.FTIRspectrashowstrongtransmittancepeaksa”
Dhanu 等 - 2020 - Photoluminescence of mixed phase CaSiO3Ce3+ nanop DOI: 10.1016/j.ijleo.2020.165139 -
Acetate affidabilità 1,0
“FTIR analysis resulting in bands of C-O at 998 Ti-O-Ti at 506 and cm-1.”
Nurdiansah 等 - 2020 - Synthesis of ZnOrGOTiO2 Composite and Its Photoc DOI: 10.1088/1757-899X/833/1/012028 -
Amide affidabilità 1,0
“1), (1335cm-1),14 (998cm-1) 169 C-N stretching Si-O-Si stretching and Mg-N stretching (a small hump 435cm-1).”
Removal of hazardous pollutants from wastewater: Catalytic applications of Mg nanoparticle functionalized aminoclay DOI: 10.1016/j.molliq.2019.112005 -
Hydroxyl (O-H) affidabilità 1,0
“2 2 C-O 1168 stretching vibration O-H 998 bending vibration of hydroxymethyl C-N-H”
Cheng 等 - 2022 - Development of a High-Strength and Adhesive Polyac DOI: 10.1021/acsomega.1c06626 -
Silicon (Si) affidabilità 1,0
“The most inaction (Figure 3(b)), the morphology of the geopolymer is tensive band at 998 was due to Si-O-Al stretching vi757cm-1 constituted by a chain of polysilicate layers by the combration.”
El Alouani 等 - 2019 - Preparation, Characterization, and Application of DOI: 10.1155/2019/4212901 -
Hydrogen bond affidabilità 1,0
“The peak at 998 is attributed to intramolecular hydrogen bonding of hydroxyl groups or the water plasticizattributed to intramolecular hydrogen bonding of hydroxyl groups or the water plasticizing”
Morphology and Selected Properties of Modified Potato Thermoplastic Starch DOI: 10.3390/polym15071762 -
Alkyl C-H affidabilità 1,0
“Pure Materials Absorption Bands (cm-1) Bands Assignment (cm-1) Pure Materials Bands Assignment Absorption Bands βCD 998 C-H bending 1077 -S=O stretching βCD 998 C-H bending”
Effects of Cyclodextrins ( and ) and l-Arginine on Stability and Functional Properties of Mucoadhesive Buccal Films Loaded with Omeprazole for Pediatric Patients DOI: 10.3390/polym10020157
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