Abstract
Because of the highly corrosion resistant properties of hopeite crystals doped with manganese Zn3-xMnx(PO4)2·4H2O, EXAFS was applied to analyse the structure. Oxygen atom was found to exist at 1.62Å from manganese atom. However, since φ(K) of a Fourier transform contains a certain phase shift deviation, an inverse Fourier transform and curve fitting were carried out to determine the real bond distance, 2.15Å. There was a difference of approximately 0.5Å between the Mn-O distances obtained by the EXAFS Fourier transform and inverse Fourier transform, and this discrepancy was found to be due to the phase shift deviation. The coordination number for manganese atoms obtained from the 1st peak was 6.8. It was found that the bond distance of 2.15Å corresponds to the Mn-O bond due to the octahedral structure of MnO2(H2O)4 in the hopeite crystals.
Inverse Fourier transform and curve fitting of the 2nd to 4th peaks indicated that all the peaks belonged to the Mn-P bond. The coordination number of phosphorus to manganese for the 2nd peak was 1.0. Therefore, the 2nd peak provided information about the closest phosphorus to manganese in the MnO2(H2O)4 groups.
