• Top library match: azane; formic acid #28915

• The low wavenumber band at 1102 cm⁻¹ assigned to C-S bonding [4] is not obviously corroborated by other sulfate or sulfonate absorptions in the spectrum; it may represent a minor component or a different functional group such as C-O.
• The library match confidence is low (0.15) and the Top-1 candidate (azane;formic acid) does not fully account for the observed aromatic and amide signals; therefore the material remains classified only at a functional-group level.
• The assignment of the 3160 cm⁻¹ band to aromatic C-H depends heavily on a single literature source [1] and could alternatively be interpreted as an N-H stretch in a hydrogen-bonded amide environment.

Recommended next steps: Confirm the presence of amide groups by performing a ninhydrin test or by acquiring an N 1s XPS spectrum. If the sulfur assignment at 1102 cm⁻¹ is critical, examine the sample by SEM-EDS or elemental analysis to verify sulfur content. Consider GC-MS or Py-GC/MS analysis to identify specific low-molecular-weight fragments that can refine the chemical class.