What absorbs at 695 cm⁻¹ in an FTIR spectrum?

Quick answer

A band near 695 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 695 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

• confidence 1.0

  “evidenced by the appearance of a new peak at 695 The flammability was also performed with the limiting oxygen assigned to the N-H bending vibration, and two new bands cm-1and cm-1, index (LOI) test on a Stanton Redcroft oxygen index meter a”

  Effect of Surface Functionalization of SiO2 Nanoparticles on the Dynamic Mechanical, Thermal and Fire Properties of Wheat Straw/LDPE Composites DOI: 10.1007/s10924-019-01576-y
• Aromatic ring confidence 1.0

  “The ratio between -1 peak appears at 695 cm due to aromatic C-C angular -1 the heights of the bands at 1372 and 2900 cm was used deformation in both materials (Fig.”

  Uner 等 - 2016 - Centaurea solstitialis and Silybum marianum weeds DOI: 10.1007/s13726-015-0396-2
• Silicon (Si) confidence 1.0

  “The absorption at 460 asymmetrical bending vibration of the Si-O-Si bond [24], 3.2 Analysis by FTIR The presence of symmetrical bending vibration of the Si-O cm-1 indicates that quartz in our samples is group at 695 cm-1 is in crystalline f”

  Mineralogical Analysis of Sand Roses and Sand Dunes Samples from Two Regions of South Algeria DOI: 10.1007/s12633-018-9974-1
• Aromatic ring confidence 1.0

  “The band at 960 cm-1 is associated with the out-of-plane deformation like band" is related to the vibration mode of N=Q=N (Q represents the quinoid ring), of C-H in the 1,4-disubstituted benzene ring, and 603 cm-1 and 695 cm-1 correspond to”

  Preparation of Anionic Surfactant-Based One-Dimensional Nanostructured Polyaniline Fibers for HydrogenStorage Applications DOI: 10.3390/polym15071658
• Protein beta sheet confidence 1.0

  “cm-1 In the amide I region, IR bands in the 695~1660 are assigned to beta sheet, cm-1 cm-1 1660~1650 to the alpha-helix structure, 1650~1640 to random structure, and”

  The synthesis of hydroxyapatite with different crystallinities by controlling the concentration of recombinant CEMP1 for biological application DOI: 10.1016/j.msec.2015.10.029
• Ring structure confidence 1.0

  “C-H deformation vibration of ring hydrogens 848 C-H deformation vibration 695 Ring deformation vibration cm-1;”

  Effect of Phenolic Resin on the Rheological and Morphological Characteristics of Styrene-Butadiene Rubber-Modified Asphalt DOI: 10.3390/ma13245836
• Acetate confidence 1.0

  “Fourier Transform Infrared (FTIR, Nicolet iZ10, Thermo Fisher Scientific, Inc., Madison, cm-1): WI, USA) (KBr, 1778 (asymmetrical C=O stretch vibration) and 1720 (symmetrical C=O stretch 13C vibration), 1357 (C-N stretch vibration), 695 (C=”

  Feng 等 - 2019 - Flame Inhibition and Charring Effect of Aromatic P DOI: 10.3390/polym11010074
• confidence 1.0

  “In the spectrum obtained for pristine alumina, the following bands characteristic for this compound appear: the O-H stretching band in the wavelength range of 3600-3200 cm-1, the O-H bending oscillation band originating from the water physi”

  Klapiszewska 等 - 2019 - Production of cement composites using alumina-lign DOI: 10.5277/ppmp19058