What absorbs at 917 cm⁻¹ in an FTIR spectrum?
A band near 917 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 917 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 | 3 | 3 | 1.0 |
| Silicon (Si) | 2 | 2 | 1.0 |
| Hydroxyl (O-H) | 2 | 2 | 1.0 |
| C c single bond | 2 | 2 | 1.0 |
| Phosphate (PO4) | 2 | 2 | 0.9 |
| Siloxane (Si-O-Si) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| Silicon nitrogen | 1 | 1 | 1.0 |
| Metal hydroxyl | 1 | 1 | 0.9 |
| Oxygen heterocycle | 1 | 1 | 0.8 |
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 |
|---|---|---|---|
| HAp | 917, 3572, 962 | Hydroxyl (O-H), Alkyl C-H | 1 |
| calcium phosphate | 917, 1070, 1149 | Hydroxyl (O-H), Alkyl C-H | 1 |
| lignin | 917, 1035, 1510 | Alkyl C-H, Hydroxyl (O-H) | 1 |
| PVA | 917, 1660, 2930 | Alkyl C-H, Hydroxyl (O-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 917 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
-
Silicon nitrogen confidence 1.0
“Fourier transform infrared (FTIR) spectroscopy cm-1 analysis showed the Si-N-Si stretching peak at 917 further, the full width at half maxima and Si-N-Si peak position showed their dependency on the deposition temperature.”
Deposition of Silicon Nitride Films using Chemical Vapor deposition for Photovoltaic Applications DOI: 10.1016/j.rinp.2016.11.029 -
C c single bond confidence 1.0
“cm-1 to the CH bending of an alkyl group, 1665 to C=O stretching, the intense bands at 1000 2 cm-1 cm-1 region are due to the C-O and C-C stretch vibrations, and bands at 917 are assigned to C-C stretching [21,22].”
Delgado-Mellado 等 - 2018 - Thermal stability of choline chloride deep eutecti DOI: 10.1016/j.molliq.2018.03.076 -
Alkyl C-H confidence 1.0
“explicit assignment”
Kibedi-Szabo 等 - 2012 - Biodegradation Behavior of Composite Films with Po DOI: 10.1007/s10924-011-0391-4 -
Hydroxyl (O-H) confidence 1.0
“cm-1, ν stretching mode of PO and HPO at 1077 1093 and 1121 with 3 cm-1 the faint but characteristic line of OCP HPO 4(6) [P-(OH)], stretch at 917 and O-H incm-1 plane bending around 1295 were clearly seen at the 78 h time point cm-1), (Fig”
Exploring the Formation Kinetics of Octacalcium Phosphate from Alpha-Tricalcium Phosphate: Synthesis Scale-Up, Determination of Transient Phases, Their Morphology and Biocompatibility DOI: 10.3390/biom13030462 -
Lignin confidence 1.0
“In 1110 peak, lignin (a), (b), (c) and (d) showed aromatic C-H aromatic C-H deformation of syringyl units, while in 917 cm-1, lignin (a) and (b) showed C-H bending cm-1,”
Prasetyo 等 - 2020 - Lignin Refinery Using Organosolv Process for Nanop DOI: 10.3390/molecules25153428 -
Alkyl C-H confidence 1.0
“C-H out-of-plane bend C-O stretching 999 - - C-O stretching - 917 - C-H out-of-plane bend - 917 -”
Identification of Three Dalbergia Species Based on Differences in Extractive Components DOI: 10.3390/molecules23092163 -
Hydroxyl (O-H) confidence 1.0
“The absorption at 917 assigned to O-H out-of-plane swing vibration of assigned to O-H out-of-plane swing vibration of cm-1”
The Synthesis and Characterization of Novel Bis-cationic Asphalt Emulsifier DOI: 10.1051/matecconf/201713004004 -
confidence 1.0
“The peak at 787 cm-1 is due to Si-O-Si vibrations and FTIR spectrum in the region of 917 and 675 cm-1 are derived from OH groups bound to silanol groups (Si-OH-Al) [35] and influenced by the presence of Fe ions [33], which remain after the”
Bentonites Modified with Phosphomolybdic Heteropolyacid (HPMo) for Biowaste to Biofuel Production DOI: 10.3390/ma12091431
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