What absorbs at 644 cm⁻¹ in an FTIR spectrum?
A band near 644 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 5 cited sources
Jawapan pantas
A band near 644 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.
Penetapan kumpulan berfungsi yang mungkin
| Kumpulan berfungsi | Fakta sokongan | Sumber dipetik | Keyakinan tertinggi |
|---|---|---|---|
| Aromatic ring | 2 | 2 | 1.0 |
| Alkyl C-H | 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 |
| Metal oxygen | 1 | 1 | 1.0 |
| Sulfur | 1 | 1 | 0.9 |
Pemeringkatan mencerminkan bukti literatur terkumpul, bukan satu peraturan berwibawa. Sentiasa sahkan terhadap konteks sampel anda.
Bahan yang mungkin
| Bahan | Puncak sokongan | Kumpulan bertindih | Sumber dipetik |
|---|---|---|---|
| PVC | 644, 834, 1195 | Alkyl C-H, Methoxy (OCH3), Methacrylate | 1 |
| DNA | 644, 1712, 1660 | Methacrylate, Methoxy (OCH3) | 1 |
| plasma | 644, 1656, 1650 | Alkyl C-H, Methacrylate | 1 |
Bahan hanya dipaparkan apabila kumpulan literatur yang sama menyokong jalur ini dan sekurang-kurangnya satu puncak ciri tambahan.
Logik spektrum
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 644 cm⁻¹ is usually not enough for material identification by itself.
Penggunaan dunia sebenar
Jenis pertanyaan ini biasa dalam pengenalpastian polimer, saringan plastik tidak diketahui, penyelesaian masalah QC, pengesahan bahan kitar semula, dan semakan tugasan puncak yang disokong oleh literatur.
Kesilapan biasa
- Menganggap satu jalur terpencil sebagai bukti bahan tanpa memeriksa sekurang-kurangnya satu atau dua puncak sokongan.
- Mengabaikan pertindihan: pelbagai kumpulan berfungsi boleh menyumbang berhampiran nombor gelombang yang sama.
- Melangkau pengesahan apabila bahan tambahan, campuran, pengoksidaan, atau pencemaran boleh memesongkan spektrum.
Nasihat pengesahan
Apabila kekaburan masih ada, sahkan hipotesis dengan DSC, GC-MS, atau TGA, terutamanya untuk campuran, sampel terdegradasi, dan polimer terisi.
Literatur di sebalik penetapan ini
-
Metal oxygen keyakinan 1.0
“at octahedral sites and consequently results in a decrease in the saturation magnetization [50] symmetric stretching of M - O at medium 644 [62], and an increase in the coercivity according to equation (6) [63]: octahedral sites 2 K”
Low-temperature synthesis of Sr2FeMoO6 double perovskite; structure, morphology, and magnetic properties DOI: 10.1016/j.ceramint.2020.03.264 -
Aromatic ring keyakinan 1.0
“Smaller peak at 643.806 corresponds to the substituted benzene group [3, 12, 16].”
Treated Rhizophora mucronata tannin as a corrosion inhibitor in chloride solution DOI: 10.1371/journal.pone.0200595 -
Acetate keyakinan 1.0
“plane bend), (C-O stretching of alcoholic 644cm-1 Te prepared Sn(Fe:Ni)O groups), and (aromatic C-H out-of-plane bendnanoparticles were well crys-”
Aloufi - 2023 - Assessment of Structural, Optical, and Antibacteri DOI: 10.1155/2023/5494592 -
Sulfur keyakinan 0.9
“Text: 's(SO3) ... peaks at 644'”
Ramesh 和 Yi - 2009 - FTIR spectra of plasticized high molecular weight DOI: 10.1007/s11581-008-0279-z -
keyakinan 0.8
“Part of range 637-644 assigned to ring breathing modes.”
Vibrational Spectroscopy of Liquid Biopsies for Prostate Cancer Diagnosis DOI: 10.1177/1758835920918499
Ada spektrum dengan jalur ini?
Muat naik spektrum FTIR anda dan dapatkan laporan tafsiran penuh — penetapan puncak dengan petikan literatur, padanan perpustakaan, dan rantaian bukti berkadar keyakinan — dalam beberapa saat.