What absorbs at 1031 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 1031 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

Ranking reflects accumulated literature evidence, not a single fixed rule. Always confirm against your sample context.

Possible materials

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 1031 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

• Alkyl C-H confidence 1.0

  “A peak 1031 which has been assigned to a combination of C-H in-plane ring bending and the five-membered ring deformation which contains the C=C-N deformation.”

  Highly Biological Active Antibiofilm, Anticancer and Osteoblast Adhesion Efficacy from MWCNT/PPy/Pd nanocomposite DOI: 10.1016/j.apsusc.2017.10.142
• C-O single bond confidence 1.0

  “asymmetric O-C-C stretch ester: 1031.2 stretch: 1054.2 mucus.”

  Elkins - 2011 - Rapid Presumptive Fingerprinting of Body Fluids DOI: 10.1111/j.1556-4029.2011.01870.x
• Phosphate (PO4) confidence 1.0

  “At 24 h (Figure 5A), in all thicknesses, nesses, the behavior is similar: a peak corresponding to the presence of OH bonds, folthe behavior is similar: a peak corresponding to the presence of OH bonds, followed cm-1, lowed by a peak corresp”

  Remineralization Potential of Three Restorative Glass Ionomer Cements: An In Vitro Study DOI: 10.3390/jcm12062434
• Carbonyl (C=O) confidence 1.0

  “An intense peak cm-1 appeared at 1031 with the incorporation of CNC into Tylose MH 50 film, which is cmassigned to CO stretching (carbonyl groups) (Figure 2D).”

  Mustary 等 - 2023 - Synthesis and Characterization of Biocomposite Fil DOI: 10.33263/BRIAC133.274
• Amine primary confidence 1.0

  “3650-3250cm-1 cm-1 cm-1 cm-1 1010.16 and 922.53 ±1050 (Medium) -COOH (C-O Stretching) -NH2 (N-HStretching) (Medium) 1638.22cm-1 1650-1590cm-1 -NH2 (N-HBending) (Medium) cm-1 cm-1 3650-3250 (Medium) -NH2 (N-H Stretching) 3445.97 1030.64cm-1”

  Validation of the Developed Zero-Order Infrared Spectrophotometry Method for Qualitative and Quantitative Analyses of Tranexamic Acid in Marketed Tablets DOI: 10.3390/molecules26226985
• N h confidence 1.0

  “The peak at 1229 S@O was identified as sulfones, sulfonyl chlorides, sulfates, sulfoncm(cid:1)1 CAN amides, peak at 1031 corresponds to amines, and the cm(cid:1)1 CAH peaks at 979 and 758 were assigned to out of plane”

  Green synthesis of Silver nanoparticles using Streptomyces hirsutus strain SNPGA-8 and their characterization, antimicrobial activity, and anticancer activity against human lung carcinoma cell line A549 DOI: 10.1016/j.sjbs.2021.08.084
• Amide confidence 1.0

  “Besides, the characteristic peak at cm-1 1031.37 is assigned to the asymmetric stretching vibration of C-N-C of the oxazine ring, which emerges from an important band of overlapped peaks due to C-O stretching and O-H in plane deformation of”

  Tan 等 - 2018 - Synthesis and Characterization of Polybenzoxazine DOI: 10.1063/1.5066866
• C-O single bond confidence 1.0

  “The C-O-C stretch appears at 1031 The stretch appears at 1031 while the 42 cm-1 peaks at 892, 771 and 643 were attributed to the polymer backbone bending.”

  Zaman 等 - 2018 - Synthesis of thiolated arabinoxylan and its applic DOI: 10.1088/1748-605X/aa9d69