What absorbs at 1386 cm⁻¹ in an FTIR spectrum?
A band near 1386 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 1386 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 | 9 | 9 | 1.0 |
| Amide | 5 | 5 | 1.0 |
| Hydroxyl (O-H) | 3 | 3 | 1.0 |
| Secondary amine | 3 | 3 | 1.0 |
| C n single bond | 3 | 3 | 1.0 |
| C-O single bond | 3 | 3 | 1.0 |
| N h | 3 | 3 | 1.0 |
| Carboxyl (COOH) | 3 | 3 | 1.0 |
| Alkene (C=C) | 2 | 2 | 1.0 |
| Methyl | 2 | 2 | 1.0 |
| Water (H2O) | 2 | 2 | 1.0 |
| Silanol (Si-OH) | 1 | 1 | 1.0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1.0 |
| Lignin | 1 | 1 | 1.0 |
| N eq o | 1 | 1 | 1.0 |
| Aromatic ring | 1 | 1 | 1.0 |
| Ring structure | 1 | 1 | 1.0 |
| C c single bond | 1 | 1 | 1.0 |
| Ketone | 1 | 1 | 1.0 |
| Ester | 1 | 1 | 1.0 |
| Carbonyl (C=O) | 1 | 1 | 1.0 |
| Methoxy (OCH3) | 1 | 1 | 1.0 |
| Methacrylate | 1 | 1 | 1.0 |
| Acetate | 1 | 1 | 1.0 |
| Protein beta sheet | 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 |
|---|---|---|---|
| pMMA | 1386, 1722, 1383 | Alkyl C-H | 1 |
| graphene oxide | 1386, 1150, 3400 | Hydroxyl (O-H), Alkyl C-H | 1 |
| silver nanoparticles | 1386, 1636, 1631 | 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 1386 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
“The peak at 1533 is caused by N-O stretching of aromatic nitro cm-1 compounds, the peak at 1386 is caused by symmetric carboxylate stretching, and the peak at 1327 is caused by N-O asymmetric stretching and reveals the presence of a nitro c”
Nematicidal activity of seaweed-synthesized silver nanoparticles and extracts against Meloidogyne incognita on tomato plants DOI: 10.1038/s41598-022-06600-1 -
Protein beta sheet confidence 1.0
“β-Sheet of amide II [59-61] vibration 1386 Stretching and bending ](C-H)”
Hssaini 等 - 2022 - Do Pollination and Pollen Sources Affect Fig Seed DOI: 10.1155/2022/3969165 -
Hydroxyl (O-H) confidence 1.0
“ECS Journal of Solid State Science and Technology, 6 (7) R88-R95 (2017) R91 cm-1 cm-1 The absorption band at 3450 and 1630 can be attributed bond.51 to the symmetric stretching and bending vibration of H-O-H Theabsorptionbandobtainedat1386c”
Mondal 和 Manam - 2017 - Structural and Luminescent Properties of Si4+ Co-D DOI: 10.1149/2.0021708jss -
Hydroxyl (O-H) confidence 1.0
“A sharp peak at 1386.44 was (N-- appeared in the influent wastewater for nitro-group O bend) which O-H N-H 3417.71 and stretching, due to the Guilherme et al.”
Greenhouse gases emissions from duckweed pond system treating polyester resin wastewater containing 1,4-dioxane and heavy metals DOI: 10.1016/j.ecoenv.2020.111253 -
Alkyl C-H confidence 1.0
“Those bands are methyl group scissoring (H-C-H) at 1434 combination band at the cm-1 1386 band of methyl group scissoring (H-C-H), benzene ring bending (C-C-H) and cm-1 symmetrical stretching s(C-C-C);”
Aguilar-Rodriguez 等 - 2023 - Microanalytical Characterization of an Innovative DOI: 10.3390/molecules28020564 -
Acetate confidence 1.0
“These diffraction peaks 1585cm-1 bands at 1386, 1720, and assigned to C-O, C=O, couldbereadilyindexedtocubicstructure(JCPDS09-0412).”
Al-Garni 等 - 2017 - Synthesis of Propylene Carbonate from Epoxide and DOI: 10.1155/2017/5641604 -
Water (H2O) confidence 1.0
“The broad peak-like feature shown at at 1386 cm-1 3446 shows the presence of moisture in graphene oxide powder[16,17].”
Influence of Reduced Graphene Oxide on Effective Absorption Bandwidth Shift of Hybrid Absorbers DOI: 10.1371/journal.pone.0153544 -
Alkyl C-H confidence 1.0
“The band at 986 is the bands at 1386.5 and 748 cm-1 are attributed to the α-methyl group vibrations.”
Awad 等 - 2020 - Experimental Investigation of Methyl Methacrylate DOI: 10.3390/ma13245793
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