What absorbs at 433 cm⁻¹ in an FTIR spectrum?
A band near 433 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 433 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 |
|---|---|---|---|
| Metal oxygen | 3 | 3 | 1.0 |
| Phosphate (PO4) | 2 | 2 | 1.0 |
| Water (H2O) | 1 | 1 | 1.0 |
| Hydroxyl (O-H) | 1 | 1 | 1.0 |
Ranking reflects accumulated literature evidence, not a single authoritative rule. Always confirm against your sample context.
Possible materials
| Material | Supporting peaks | Overlapping groups | Cited sources |
|---|---|---|---|
| SiO2 | 433, 1739, 699 | Hydroxyl (O-H), Metal oxygen | 1 |
| hydroxyapatite | 433, 1620, 1639 | Phosphate (PO4), 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 433 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
-
Phosphate (PO4) confidence 1.0
“592cm(cid:1)1 showed the same peaks at 433 and due to internal O492 1.7m2/g) perature was greater at 0% (from 5.7 to and 5% SAID 430 963cm(cid:1)1 43(cid:1) PAO P-O vibration, at due to of the PO and at 1040 493 1.6m2/g) 1.4m2/g) (from 4.7”
Structure reinforcement of porous hydroxyapatite pellets using sodium carbonate as sintering aid: Microstructure, secondary phases and mechanical properties DOI: 10.1016/j.apt.2019.05.013 -
Metal oxygen confidence 1.0
“4]2(cid:2) 711-933cm(cid:2)1, tetrahedrons was detected at and The strong W-O stretching in [WO 433cm(cid:2)1.”
Phuruangrat 等 - 2010 - Synthesis, characterisation and photoluminescence DOI: 10.1080/17458080903513276 -
confidence 1.0
“From Fourier Transform Infrared cm-1 Spectroscopy (FTIR), the band at 433 is attributed to Zn-O bond Key words: Nanoparticles, Optical properties, XRD”
Pandiyarajan 和 Karthikeyan - 2011 - Optical, phonon and structural analysis of Na dope DOI: 10.1117/12.890082 -
Metal oxygen confidence 1.0
“From the FTIR spectrum, a strong peak of 862 has been obtained due to the 42cm-1 stretching vibration of WO in scheelite structure, and a weak but sharp band at 433 has been noticed due to the metal-oxygen (Ca-O) band.”
Abozaid 等 - 2018 - Characterization of Neodymium Doped Calcium Tungst DOI: 10.2298/SOS1804445A -
Phosphate (PO4) confidence 1.0
“The peaks at 433 cm-1 and 447 cm-1 were assigned to PO43υ2 vibration (bending mode), and the peaks at 1030 cm-1, 1047 cm-1 and 1079 cm-1 (arb.”
Gavinho 等 - 2023 - An Eco-Friendly Process to Extract Hydroxyapatite DOI: 10.3390/jfb14050279 -
Hydroxyl (O-H) confidence 1.0
“The first 3,630 The stretching and bending vibrations of the one (up to 433 K) is attributed to the dehydration of the hydroxyl groups of water molecules present in the clay can cm-1,”
Natkanski 等 - 2013 - Effect of Fe3+ ions present in the structure of po DOI: 10.1007/s10973-013-3225-x -
confidence 0.9
“Text: '433 are attributed to ... N bending vibrations'”
Francis 等 - 2016 - Optical nonlinearity in multiferroic bismuth ferri DOI: 10.1016/j.jallcom.2016.07.094 -
confidence 0.7
“Lewis Al2Cl peaks assigned”
Understanding the molecular structure of the elastic and thermoreversible AlCl3:urea/polyethylene oxide gel electrolyte DOI: 10.1002/cssc.202001557
Have a spectrum with this band?
Upload your FTIR spectrum and get a full interpretation report — peak assignments with literature citations, library matches, and a confidence-rated evidence chain — in seconds.