After releasing the pressure, RO-Fe2O3 and PPV-Fe2O3 spontaneously reverted to the more thermodynamically stable α-Fe2O3 polymorph. However, strikingly, the ζ-Fe2O3 phase retained its crystal structure after the pressure release. The presence of α-Fe2O3 and ζ-Fe2O3 phase in the sample after the pressure release was further evidenced by analyzing selective area electron diffraction (SAED) pattern where planes belonging to α-Fe2O3 and ζ-Fe2O3 phase were identified (other, not assigned planes most probably come from the matrix to which the sample was pressed). Moreover, the sample after pressure release features nanoparticles with an average particle size of 66.2 nm and lognormal particle size distribution from ~8 to ~150 nm, significantly broadening the diffraction lines in the XRD patterns. Then, the lattice constants of ζ-Fe2O3 at room temperature and atmospheric pressure were found to be a = 9.863 Å, b = 10.00 Å, c = 8.949 Å, β = 101.10° and V = 850.4 Å3 and its crystal structure falls within the I2/a space group. The crystal structure of stable ζ-Fe2O3 and; the atomic coordinates of the iron and oxygen sites in the ζ-Fe2O3 crystal structure are listed, together with lattice parameters, cell volume, and Rwp-factor. If you are looking for high quality, high purity, and cost-effective Iron oxide, or if you require the latest price, please feel free to email contact mis-asia.