Chemical and structural characterization of natural phosphate of Hahotoe (Togo)

Abstract

 Chemical and structural characterizations of natural phosphates of Hahotoe (Togo) have been performed. From chemical analysis and FTIR study, it can be concluded that the material is carbonated fluoroapatite with poor substitution of calcium by cadmium and manganese. From these results, the molecular formula proposed is:

Ca_9.925Cd_0.004Mn_0.013[(PO₄)_5.886(CO₃)_0.113]F₂.

Powder X-ray diffraction fitting results confirm that compound belongs to the apatite family crystallising in the hexagonal system, space group P6₃/m. The cell parameters are: a = 9.3547(5) Å; c = 6.8929(4) Å.

KEY WORDS: Natural phosphate, Fluoroapatite, Infrared, X-Ray diffraction, Rietveld structure refinement

Bull. Chem. Soc. Ethiop. 2003, 17(2), 139-146.