FTIR FUNCTIONAL GROUP

Silicon-oxygen (Si-O) — FTIR absorption peaks and assignments

These are the characteristic FTIR wavenumbers where Silicon-oxygen (Si-O) tends to absorb, compiled from published literature and ranked by supporting evidence. Each assignment is traceable to a source (DOI) and cross-validated against our 130,000+ reference spectra and knowledge graph.

Backed by 8 cited sources

Quick answer

Silicon-oxygen (Si-O) is usually assigned by looking for a recurring cluster of characteristic peaks rather than one exact textbook number. The table below shows where the literature most often places this group in FTIR, ranked by accumulated evidence.

Characteristic FTIR peaks for Silicon-oxygen (Si-O)

Wavenumber (cm⁻¹) Supporting facts Cited sources Top confidence
800 63 57 1.0
1100 59 49 1.0
1000 52 48 1.0
1080 42 37 1.0
1030 24 22 1.0
460 22 21 1.0
795 18 16 1.0
1090 17 16 1.0
470 17 15 1.0
1050 17 15 1.0
1200 17 14 1.0
960 16 13 1.0
798 15 15 1.0
950 15 14 1.0
1060 15 14 1.0
1035 14 14 1.0
900 14 13 1.0
1040 14 13 1.0
796 13 11 1.0
930 13 10 1.0
980 12 12 1.0
1036 12 12 1.0
1075 12 12 1.0
780 12 11 1.0
1070 12 11 1.0
790 12 11 1.0
600 12 11 1.0
1082 12 10 1.0
1097 11 10 1.0
450 11 10 1.0

Showing the 30 best-supported peaks of 762 total for Silicon-oxygen (Si-O).

Possible materials

Material Supporting peaks Cited sources
SiC 791, 805, 1136 1
silica 1100, 1080, 800 1

Spectrum logic

A functional-group assignment becomes more confident when several expected bands appear together. Use this page to find the strongest-supported peaks, then confirm that the same sample exhibits a coherent pattern rather than a single isolated hit.

Real-world usage

These pages are useful for unknown material analysis, peak explanation in reports, polymer troubleshooting, and verifying whether a candidate material family is chemically plausible.

Common mistakes

  • Using one functional-group page as a complete material verdict without checking the rest of the spectrum.
  • Assuming the strongest band is always the most diagnostic one.
  • Forgetting that processing, additives, aging, and mixtures can shift or broaden expected peaks.

Verification advice

Use DSC, GC-MS, or TGA when several material families share similar bands or when mixture effects make the FTIR assignment uncertain.

Literature behind these assignments

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