**Analysis:** * **721 & 741 cm⁻¹:** Within the range for out-of-plane bending vibrations of aromatic C-H bonds (typically 900-675 cm⁻¹) or possibly metal-oxygen (M-O) vibrations from inorganic/organometallic species. The broadness suggests a complex or coupled vibration. * **1396 & 1455 cm⁻¹:** The 1455 cm⁻¹ band is characteristic of asymmetric bending (scissoring) of methylene (CH₂) groups. The 1396 cm⁻¹ band could correspond to symmetric bending of a methyl (CH₃) group or O-H bending of carboxylic acids. * **1534 cm⁻¹:** A strong, broad band in the 1570-1510 cm⁻¹ range is highly characteristic of the asymmetric stretching vibration (νₐs) of a carboxylate anion (COO⁻). This is a key diagnostic feature. * **2846 & 2914 cm⁻¹:** The 2914 cm⁻¹ band is assigned to the asymmetric C-H stretching of methylene (CH₂) groups. The sharp 2846 cm⁻¹ band is assigned to the symmetric C-H stretching of methylene (CH₂) groups. This pattern indicates the presence of long aliphatic chains.
**Conclusion:** The FTIR spectrum indicates the presence of a **carboxylate salt** (COO⁻), evidenced by the strong asymmetric stretch at 1534 cm⁻¹. The sample contains significant **aliphatic hydrocarbon chains** (methylene groups), indicated by C-H stretches at 2846/2914 cm⁻¹ and the scissoring mode at 1455 cm⁻¹. The weak bands below 800 cm⁻¹ are ambiguous but may suggest aromatic substitution patterns or the presence of metal cations associated with the carboxylate. The absence of a strong, sharp O-H stretch (~1700 cm⁻¹) rules out a free carboxylic acid as the major component.
**[Inference]** Based on the combined evidence of a carboxylate ion and long aliphatic chains, the sample is most likely a **metal salt of a long-chain fatty acid (a soap or metal carboxylate)**, such as a stearate or palmitate. The specific metal cation cannot be determined from this data alone. The broad nature of the carboxylate and low-wavenumber bands may indicate a crystalline or polymeric structure, or the presence of water/hydration.
This discussion presents an infrared spectral analysis combining
automated interpretation with reference comparison to support
functional group identification and structural assessment.
FTIR Spectrum Interpretation Summary
Comparative Analysis Conclusion
AI-assisted Interpretation Conclusion
**Data:**
* 721 cm⁻¹: weak, broad
* 741 cm⁻¹: weak, broad
* 1396 cm⁻¹: medium, broad
* 1455 cm⁻¹: medium, broad
* 1534 cm⁻¹: strong, broad
* 2846 cm⁻¹: weak, sharp
* 2914 cm⁻¹: medium, broad
**Analysis:**
* **721 & 741 cm⁻¹:** Within the range for out-of-plane bending vibrations of aromatic C-H bonds (typically 900-675 cm⁻¹) or possibly metal-oxygen (M-O) vibrations from inorganic/organometallic species. The broadness suggests a complex or coupled vibration.
* **1396 & 1455 cm⁻¹:** The 1455 cm⁻¹ band is characteristic of asymmetric bending (scissoring) of methylene (CH₂) groups. The 1396 cm⁻¹ band could correspond to symmetric bending of a methyl (CH₃) group or O-H bending of carboxylic acids.
* **1534 cm⁻¹:** A strong, broad band in the 1570-1510 cm⁻¹ range is highly characteristic of the asymmetric stretching vibration (νₐs) of a carboxylate anion (COO⁻). This is a key diagnostic feature.
* **2846 & 2914 cm⁻¹:** The 2914 cm⁻¹ band is assigned to the asymmetric C-H stretching of methylene (CH₂) groups. The sharp 2846 cm⁻¹ band is assigned to the symmetric C-H stretching of methylene (CH₂) groups. This pattern indicates the presence of long aliphatic chains.
**Conclusion:**
The FTIR spectrum indicates the presence of a **carboxylate salt** (COO⁻), evidenced by the strong asymmetric stretch at 1534 cm⁻¹. The sample contains significant **aliphatic hydrocarbon chains** (methylene groups), indicated by C-H stretches at 2846/2914 cm⁻¹ and the scissoring mode at 1455 cm⁻¹. The weak bands below 800 cm⁻¹ are ambiguous but may suggest aromatic substitution patterns or the presence of metal cations associated with the carboxylate. The absence of a strong, sharp O-H stretch (~1700 cm⁻¹) rules out a free carboxylic acid as the major component.
**[Inference]**
Based on the combined evidence of a carboxylate ion and long aliphatic chains, the sample is most likely a **metal salt of a long-chain fatty acid (a soap or metal carboxylate)**, such as a stearate or palmitate. The specific metal cation cannot be determined from this data alone. The broad nature of the carboxylate and low-wavenumber bands may indicate a crystalline or polymeric structure, or the presence of water/hydration.
This discussion presents an infrared spectral analysis combining automated interpretation with reference comparison to support functional group identification and structural assessment.