Synthesis of Nano‐γ‐Ferric Oxide by Thermolysis of the 2‐Mercapto‐5‐Methylpyridine‐N‐Oxide‐Iron(III) Complex via Factorial Design

2‐Mercapto‐5‐methylpyridine‐N‐oxide (MMPNO) and its sodium salt (NaMMPNO) were synthesized. The reaction of the latter with Fe³⁺ generates Fe(MMPNO)₃ chelate. The thermolysis of this chelate at 350 °C yielded highly pure reddish‐brown γ‐Fe₂O₃ nanocrystallites with an average particle size of 6.2 nm, a particle size range of 4.2 to 14.8 nm, and a specific surface area of 51.5 m²g^–1. The thermolysis process was optimized using the 2² fractional design. Quantitative tests and characterization of products were carried out by UV‐vis spectroscopy, XRD, LLS, SEM, TGA, BET, TEM, FT‐IR, elemental microanalysis, and classical analytical measurements.