• Top library match: Disodium oxalate #142581

• No clear C=O ester or amide I band pattern is observed that would independently confirm a significant protein or polyamide fraction, reducing the likelihood of those assignments being dominant.
• The library’s medium confidence (0.81) and the small lead gap among the top candidates introduce some ambiguity about the exact metal counter‑ion (sodium, potassium, calcium, etc.).
• The presence of a C–H stretch at 2931 cm⁻¹ and the literature‑derived amide possibilities suggest that the sample is not a pure single‑component oxalate; the exact proportion of organic adjunct remains unknown.
• The 1885 cm⁻¹ band is unexplained by the oxalate model and lacks a candidate assignment in the evidence table, adding to the overall compositional uncertainty.

Recommended next steps: Confirm the oxalate identity by X‑ray diffraction or Raman spectroscopy, focusing on the 1626/1313 cm⁻¹ doublet. Perform elemental analysis (e.g., EDS or ICP) to identify the metal cation and assess the sodium content suggested by the library hit. If the weak 2931 cm⁻¹ C–H band is significant, extract the organic fraction and analyze by GC‑MS or NMR to identify the hydrocarbon additive.