iron 11 phosphate formula is a common compound, used in many industrial applications including food production, cosmetics and pharmaceuticals. It is toxic and can cause eye, skin and respiratory tract irritation.
In the present article, a new complex iron phosphate phase resulting from devitrification of 40Fe2O360P2O5 glass was obtained. The XRD pattern of the obtained material was characterized by several intense reflections that do not match any iron-phosphate phases in the database, apart from the secondary rodolicoite (berlinite) marked in the figure 1 as rhombus. However, the XRD pattern suggests that the new compound is richer in iron than glass stoichiometry, indicating that some tetrahedral iron positions have been substituted by octahedral ones.
The FT-IR spectra of the new material were recorded at 300 K. The most dominant bands are centered around 1015 cm-1 and are correlated with symmetric stretching vibrations of P-O bonds in Q0 phosphate units. These vibrations are related to the two octahedral iron positions that have almost equal IS values. In addition, there are less intense bands attributed to tetrahedral iron positions that have been 6 times less populated than the octahedral ones. These tetrahedral sites are described as the spectral component number 3.
The structural and hyperfine properties of this new complex were investigated using ab initio calculations. The calculated values of quadrupole splitting parameters (e2Q/2) are proportional to the electronic field gradients (EFG). This indicates that the iron sites in dimers and coordinated tetrahedral coordination may be resolved based on this parameter.