Crystal-chemistry and vibrational spectroscopy of ferrinatrite, Na3[Fe(SO4)3]·3H2O, and its high-temperature decomposition

The crystal structure of ferrinatrite, Na3[Fe(SO4)3]·3H2O, was refined based on a new single-crystal X-ray diffraction experiment on a sample from the type locality Sierra Gorda, Chile. The data allowed H to be successfully located and the H-bonding system to be defined. Infrared and Raman spectra are presented and discussed for this compound on the basis of the crystal structure. The Oacceptor···H–Odonor bond distances determined from the structure refinement agree well with the geometric correlation obtained from spectroscopic data. The thermal stability and dehydration process of ferrinatrite was investigated by in situ high temperature (HT) synchrotron X-ray powder diffraction, Raman and Fourier transform infrared spectroscopies.