**Analysis (Peak Assignments vs. Polystyrene Reference):** * **699, 758 cm⁻¹ (strong, broad):** Perfectly match the characteristic out-of-plane C–H bending vibrations of monosubstituted benzene ring (phenyl group), a definitive fingerprint for polystyrene. * **1452, 1492 cm⁻¹ (strong, sharp):** Correspond to aromatic ring C=C skeletal in-plane vibrations, consistent with polystyrene. * **1601 cm⁻¹ (medium, sharp):** Corresponds to aromatic ring C=C stretching, a key band for polystyrene. The weak band at 1583 cm⁻¹ is also commonly observed in its spectrum. * **2849 (weak, broad), 2923 (strong, broad):** Assigned to aliphatic C–H stretching vibrations (CH₂ asymmetric and symmetric stretches) of the polymer backbone. * **3001, 3026, 3061, 3082 cm⁻¹ (weak/strong/medium/weak, sharp):** Assigned to aromatic C–H stretching vibrations, a clear signature of the phenyl group. The pattern and relative intensities are typical for polystyrene. * **1028, 1068, 1154, 1181, 1372 cm⁻¹ (weak, broad/sharp):** These fall within regions for various C–H in-plane bending and C–C skeletal vibrations of the aromatic ring and aliphatic chain, all consistent with polystyrene's complex fingerprint region. * **906 cm⁻¹ (weak, sharp):** May correspond to C–H out-of-plane bending of the vinylidene end group or other minor structural features, which can be present depending on polymerization conditions.
**Conclusion:** The sample **is Polystyrene**. The spectroscopic evidence is conclusive. **Supporting Evidence:** The spectrum exhibits all major diagnostic peaks for atactic polystyrene with correct relative intensities and shapes: 1) The strong doublet at ~699 and ~758 cm⁻¹ is the definitive fingerprint for a monosubstituted benzene ring. 2) The strong aromatic C=C stretches at ~1452, ~1492, and ~1601 cm⁻¹ are present. 3) The C–H stretching region shows the expected clear separation between aliphatic stretches (~2923, ~2849 cm⁻¹) and the sharper aromatic stretches (3001-3082 cm⁻¹). All other observed minor peaks are consistent with the complex fingerprint vibrations of the polystyrene structure. No significant peaks contradicting the polystyrene assignment are present.
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 → Analysis → Conclusion**
**Data:**
Provided FTIR peaks (cm⁻¹, relative height, shape): 699 (1.00, strong, broad), 758 (0.75, strong, broad), 906 (0.15, weak, sharp), 1028 (0.24, weak, broad), 1068 (0.13, weak, broad), 1154 (0.11, weak, sharp), 1181 (0.12, weak, broad), 1372 (0.13, weak, broad), 1452 (1.00, strong, sharp), 1492 (1.00, strong, sharp), 1583 (0.14, weak, sharp), 1601 (0.36, medium, sharp), 2849 (0.28, weak, broad), 2923 (1.00, strong, broad), 3001 (0.17, weak, sharp), 3026 (1.00, strong, sharp), 3061 (0.42, medium, sharp), 3082 (0.29, weak, sharp).
**Analysis (Peak Assignments vs. Polystyrene Reference):**
* **699, 758 cm⁻¹ (strong, broad):** Perfectly match the characteristic out-of-plane C–H bending vibrations of monosubstituted benzene ring (phenyl group), a definitive fingerprint for polystyrene.
* **1452, 1492 cm⁻¹ (strong, sharp):** Correspond to aromatic ring C=C skeletal in-plane vibrations, consistent with polystyrene.
* **1601 cm⁻¹ (medium, sharp):** Corresponds to aromatic ring C=C stretching, a key band for polystyrene. The weak band at 1583 cm⁻¹ is also commonly observed in its spectrum.
* **2849 (weak, broad), 2923 (strong, broad):** Assigned to aliphatic C–H stretching vibrations (CH₂ asymmetric and symmetric stretches) of the polymer backbone.
* **3001, 3026, 3061, 3082 cm⁻¹ (weak/strong/medium/weak, sharp):** Assigned to aromatic C–H stretching vibrations, a clear signature of the phenyl group. The pattern and relative intensities are typical for polystyrene.
* **1028, 1068, 1154, 1181, 1372 cm⁻¹ (weak, broad/sharp):** These fall within regions for various C–H in-plane bending and C–C skeletal vibrations of the aromatic ring and aliphatic chain, all consistent with polystyrene's complex fingerprint region.
* **906 cm⁻¹ (weak, sharp):** May correspond to C–H out-of-plane bending of the vinylidene end group or other minor structural features, which can be present depending on polymerization conditions.
**Conclusion:**
The sample **is Polystyrene**. The spectroscopic evidence is conclusive.
**Supporting Evidence:** The spectrum exhibits all major diagnostic peaks for atactic polystyrene with correct relative intensities and shapes: 1) The strong doublet at ~699 and ~758 cm⁻¹ is the definitive fingerprint for a monosubstituted benzene ring. 2) The strong aromatic C=C stretches at ~1452, ~1492, and ~1601 cm⁻¹ are present. 3) The C–H stretching region shows the expected clear separation between aliphatic stretches (~2923, ~2849 cm⁻¹) and the sharper aromatic stretches (3001-3082 cm⁻¹). All other observed minor peaks are consistent with the complex fingerprint vibrations of the polystyrene structure. No significant peaks contradicting the polystyrene assignment are present.
This discussion presents an infrared spectral analysis combining automated interpretation with reference comparison to support functional group identification and structural assessment.