What absorbs at 680 cm⁻¹ in an FTIR spectrum?
A band near 680 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 680 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.
Возможные назначения функциональных групп
| Функциональная группа | Подтверждающие факты | Цитируемые источники | Максимальная достоверность |
|---|---|---|---|
| Metal oxygen | 5 | 5 | 1,0 |
| Silicon (Si) | 3 | 3 | 1,0 |
| Hydroxyl (O-H) | 2 | 2 | 1,0 |
| Silicon-oxygen (Si-O) | 2 | 2 | 1,0 |
| Methoxy (OCH3) | 2 | 1 | 1,0 |
| Methacrylate | 2 | 1 | 1,0 |
| C-O single bond | 2 | 1 | 1,0 |
| Acetate | 2 | 1 | 1,0 |
| Amide | 2 | 1 | 1,0 |
| Ring structure | 2 | 1 | 1,0 |
| Carbonate | 1 | 1 | 1,0 |
| Silicate | 1 | 1 | 1,0 |
| Siloxane (Si-O-Si) | 1 | 1 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Nitrate | 1 | 1 | 1,0 |
| Metalloid oxygen | 1 | 1 | 1,0 |
| Carbohydrate | 1 | 1 | 1,0 |
| Silicon carbon | 1 | 1 | 0,9 |
| Carbonyl (C=O) | 1 | 1 | 0,7 |
| Amine primary | 1 | 1 | 0,7 |
| Hydrogen bond | 1 | 0 | 1,0 |
| Alkyl C-H | 1 | 0 | 1,0 |
Ранжирование отражает накопленные литературные данные, а не единственное авторитетное правило. Всегда проверяйте в контексте вашего образца.
Possible materials
| Материал | Поддерживающие пики | Overlapping groups | Цитируемые источники |
|---|---|---|---|
| ZnO | 680, 1400, 3430 | Metal oxygen, Hydroxyl (O-H) | 2 |
| gelatin | 680, 1652, 3300 | Hydroxyl (O-H) | 1 |
| ZnO NPs | 680, 1664, 875 | Hydroxyl (O-H), Metal oxygen | 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 680 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.
Литература, лежащая в основе этих назначений
-
Metal oxygen достоверность 1,0
“FTIR showed a new absorption at a wavelength of 680 and 1630 which is stretching vibration of symmetry and asymmetry of the Al-O-Al.”
conferenceseries.iop.org materials science and engineering open access proceedings IOP Conferences Series: Materials Science and Engineering DOI: 10.1088/1757-899X/176/1/012049 -
Ring structure достоверность 1,0
“The strong peaks at 1295, 1260, 1200, 1080, 1030 and The peak occurring at 680, is due to out of plane ring 1000cm-1”
Nagabalasubramanian 等 - 2009 - FTIR and FT Raman spectra, vibrational assignments DOI: 10.1016/j.saa.2009.02.044 -
Carbohydrate достоверность 1,0
“The cellulose-Ag-Cu nanohybrid cm-1 polymer based nanohybrid colorimetric sensor is thermally further shows characteristics bands at 680 and 620 for stable.”
Colorimetric Based Polysorbate Crosslinked Cellulose-Ag–Cu Nanohybrid Sensor for Urea Sensing Applications DOI: 10.1007/s10924-020-01703-0 -
Metalloid oxygen достоверность 1,0
“495 26.5 474 25.7 495 43.4 Bending vibrations of Te-O-Te or O-Te-O linkages 4] 620 17.7 621 33.5 625 18.5 Stretching vibrations [TeO 680 15.2 Stretching vibrations [TeO 4]”
Rada 等 - 2009 - Structural and electronic properties of tellurite DOI: 10.1007/s10853-009-3433-8 -
достоверность 1,0
“The low wave cm-1 number region exhibits a strong vibration around 680 which corresponds to antisymmetric Ti-”
Rajakani 和 Vedhi - 2013 - Synthesis and electrochemical studies of TiO2 - Pa DOI: 10.4028/www.scientific.net/AMR.678.263 -
Nitrate достоверность 1,0
“At the low (NOcm-1 peak at 680 is probably due to nitrate frequency region, the peaks at 180, 320, 370, 410 ) 3”
Sayari 等 - 2015 - Influence of aluminium concentration in Zn0.9V0.1O DOI: 10.1515/msp-2015-0013 -
достоверность 1,0
“The peak position cm-1) of Si-O bridging stretching of omphacite (at 680 is at a lower wavenumber than”
Origin of Blue-Water Jadeite Jades from Myanmar and Guatemala: Differentiation by Non-Destructive Spectroscopic Techniques DOI: 10.3390/cryst12101448 -
достоверность 1,0
“It can be assumed that surface defects, and 680 cm-1 attributed to the Zn-O bond (Figure 5a) [35].”
Babayevska 等 - 2021 - Fabrication of Gelatin-ZnO Nanofibers for Antibact DOI: 10.3390/ma14010103
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