Sulfate (SO4) — FTIR absorption peaks and assignments

Quick answer

Sulfate (SO4) 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 Sulfate (SO4)

Showing the 30 best-supported peaks of 125 total for Sulfate (SO4).

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

• 820 cm⁻¹ confidence 1.0

  “turbinarioides (ST) 820cm-1 was related to the sulfate at the axial C-4”

  Artemisia 等 - 2019 - The Properties of Brown Marine Algae Sargassum tur DOI: 10.14499/indonesianjpharm30iss1pp43
• 452 cm⁻¹ confidence 1.0

  “The 4 cm(cid:1)1 ν2 bands at 452 and 464 correspond to the mode and 616, cm(cid:1)1 ν4 630 and 644 as the modes of barium sulfate.”

  Characterization and luminescence studies of Eu doped Barite nanophosphor DOI: 10.1016/j.jlumin.2014.01.009
• 1327 cm⁻¹ confidence 1.0

  “An IR peak at 1327.03 is assigned as anti-inflammatory, (eCeO thyroid, anti-neoplastic, anti-thrombotic antistretch present in a sulfate group [41] and stretching) [42].”

  Deepika 等 - 2017 - Photocatalytic degradation of synthetic food dye, DOI: 10.1016/j.jphotobiol.2017.10.015
• 805 cm⁻¹ confidence 1.0

  “LLM confirmed rule peak-group candidate”

  Fauzi 等 - 2020 - Characterization, Disintegration, and Dissolution DOI: 10.1155/2020/3565931
• 2514 cm⁻¹ confidence 1.0

  “The bands at 2514, cm-1 1113-1091, 1004, 672, and 604-591 were due to the presence of v 3-vibrations SO 4, v SO 1 4”

  Ilmi 等 - 2020 - Multi-analytical characterizations of prehistoric DOI: 10.1016/j.microc.2020.104738
• 1228 cm⁻¹ confidence 1.0

  “LLM confirmed rule peak-group candidate”

  In vivo prebiotic properties of Ascophyllum nodosum polysaccharide hydrolysates from lactic acid fermentation DOI: 10.1007/s10811-019-01794-w
• 1247 cm⁻¹ confidence 1.0

  “Thus, cm-1, absorption bands appear at 1247 which correspond to the vibrations of the sulfate group.”

  Kazachenko 等 - 2021 - Food Xanthan Polysaccharide Sulfation Process with DOI: 10.3390/foods10112571
• 474 cm⁻¹ confidence 1.0

  “The results of the calorimetric study of bands observed at 474 and 434 are assigned to ν ν Cs 4(AsO 4) and 2(SO 4) [20, 21].”

  Mtioui 等 - 2015 - Thermal behavior and dielectric and vibrational st DOI: 10.1007/s11581-014-1196-y