Synthesis and Characterisation of Anhydrous Magnesium Phosphate Mg$_3$(PO$_4$)$_2$


Abstract: The synthesis and characterization of anhydorus Mg_3(PO$_4)_2 was investigated. Mg_3(PO$_4)_2 is reported to have similar structural arrangements with Co_3(PO_4)_2 and \gamma-Zn_3(PO_4)_2 compounds. The sample was prepared by a new technique which is the reaction of MgCl_2.6H_2O and Na_3PO_4.12H_2O solutions at pH=5.1, which was adjusted by adding concentrated H_3PO_4 to the reaction mixture and heating the precipitated product at 600^{\circ}C untill constant weight. The purity of the product was checked by X-ray powder diffraction, IR, density measurement, SEM and DTA analysis. The monoclinic unit cell dimensions of product are a=7.605 (2), b=8.233 (3), c=5.080 (1)A^{\circ} and \beta= 94.19^{\circ} (3), which was in good agreement with the reported data for Mg_3(PO_4)_2. In the IR spectra, peaks due to PO_4 anion of T_d symmetry split because of the monoclinic crystal structure with the space group of P2_1/m. The SEM micrographs showed a spongy appearance with cavities. DTA analysis proved that anhydrous Mg_3(PO_4)_2 is stable up to melting point which is 1184^{\circ}C.

Keywords: Magneisum Phosphate, X-Ry Data of Magnesium Phosphate, SEM of Magnesium Phosphate, Microporous Materials.

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