What absorbs at 702 cm⁻¹ in an FTIR spectrum?
A band near 702 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
Быстрый ответ
A band near 702 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 |
|---|---|---|---|
| Alkyl C-H | 3 | 3 | 1,0 |
| Aromatic ring | 2 | 2 | 1,0 |
| N h | 1 | 1 | 1,0 |
| Silicon-oxygen (Si-O) | 1 | 1 | 1,0 |
| Silicate | 1 | 1 | 1,0 |
| Metal oxygen | 1 | 1 | 1,0 |
| Methoxy (OCH3) | 1 | 1 | 1,0 |
| Methacrylate | 1 | 1 | 1,0 |
| C-O single bond | 1 | 1 | 1,0 |
| Acetate | 1 | 1 | 1,0 |
| Hydroxyl (O-H) | 1 | 1 | 1,0 |
| Carboxyl (COOH) | 1 | 0 | 1,0 |
Ранжирование отражает накопленные литературные данные, а не единственное авторитетное правило. Всегда проверяйте в контексте вашего образца.
Логика спектра
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 702 cm⁻¹ is usually not enough for material identification by itself.
Использование в реальных условиях
Такой тип запроса распространен при идентификации полимеров, скрининге неизвестных пластиков, устранении неполадок в контроле качества, проверке переработанных материалов и анализе отнесения пиков на основе литературы.
Распространенные ошибки
- Рассмотрение одной изолированной полосы как доказательства материала без проверки хотя бы одного или двух поддерживающих пиков.
- Игнорирование перекрытия: несколько функциональных групп могут вносить вклад вблизи одного и того же волнового числа.
- Пропуск проверки, когда добавки, смеси, окисление или загрязнение могут исказить спектр.
Рекомендации по проверке
Когда остается неоднозначность, проверьте гипотезу с помощью DSC, GC-MS или TGA, особенно для смесей, деградированных образцов и наполненных полимеров.
Литература, лежащая в основе этих назначений
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достоверность 1,0
“The band at 996 is assigned to V O stretching of distorted octahedral and distorted cm-1 square pyramids, while the band at 702 is due to coordination of vanadium atoms with the three oxygen”
Vanadium pentoxide nanobelts: One pot synthesis and its lithium storage behavior DOI: 10.1002/crat.201200122 -
Hydroxyl (O-H) достоверность 1,0
“cm-1 (Figure S6b), respectively The band at 702 is influenced by three modes of vibration: μ 3cm-1 OH bending + O-C-O bending + C=C-(COO) bending, while the one at 729 corresponds to 13.”
Iodine Uptake by Zr/Hf-Based UiO-66 Materials: The Influence of Metal Substitution on Iodine Evolution DOI: 10.1016/S0167-8140(02)00374-2. -
достоверность 1,0
“The band observed at cm-1 702 corresponded to the Ti-O stretching and Ti-O-Ti bridging stretching bonds [30,31];”
Camila Ariza-Tarazona 等 - 2019 - New strategy for microplastic degradation Green p DOI: 10.1016/j.ceramint.2018.10.208 -
Silicate достоверность 1,0
“Silicates are represented by the intense peaks at 1989 and 1871 cm-1 [66], and by the specific peaks of quartz at 2236, 2132 and 702 cm-1, and those attributed to muscovite at”
Technological and Functional Approaches Applied to Miniature Vessels with Pigment Traces: Two Middle Bronze Age Case Studies from Eastern Subcarpathians of Romania DOI: 10.3390/app13042093 -
Alkyl C-H достоверность 1,0
“cm-1 C-H out-of-plane bending modes at 702 and 761 When a weak peak is present at 3083 and cm-1 a more intense peak at 1599 can be detected, the occurrence of a copolymer of styrene and αmethyl-styrene was suggested.”
Germinario 等 - 2016 - Chemical characterisation of spray paints by a mul DOI: 10.1016/j.microc.2015.04.016 -
Aromatic ring достоверность 1,0
“The FTIR spectrum of CIN showed principle -1 -1 The results of the assay indicated that the content in the var- -H absorption peaks at 702.04 cm and 748.33 cm (C bending -1 -1 ious solid systems prepared by different methods was in the -H o”
Multicomponent cyclodextrin system for improvement of solubility and dissolution rate of poorly water soluble drug DOI: 10.1016/j.ajps.2018.02.007 -
достоверность 1,0
“The medium strength vibrational band present at 702 The role of FTIR spectroscopy in the clinical analysis of - 1 is assigned to N-H out of plane bending with the cm normal and diabetic blood samples is clearly demonstrated.”
Ramalingam 等 - 2014 - Evaluation of metformin hydrochloride in Wistar ra DOI: 10.4103/0976-9668.136168 -
Alkyl C-H достоверность 1,0
“The band at 702 cm is likely due to overlapping peaks of the CH rocking vibration and the out-of-plane vibration of cis-disubstituted 2 olefins, related to the presence of long chain hydrocarbons [108].”
Stefanov 等 - 2013 - Towards combinatorial spectroscopy The case of mi DOI: 10.30744/brjac.2179-3425.2018.5.18.12-27
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