Synthesis and Crystal Chemistry of the Rare Earth Phosphate : HoPO4,xKOH (x≤ 1)


Authors : 

M. Zaki 1, A. Aamili 1, M. El Ghozzi 2, D. Zambon 2, M. Zahir 1, A. Sadel 1, J.C. Cousseins 2

1 Laboratoire de Physico-chimie des Matériaux, Faculté des Sciences,
P.B. 20, El Jadida, Morocco
2 Laboratoire de Chimie des Solides, Université Blaise Pascal,
F-631 77 Aubière Cedex, France

Book :

Physical Chemistry of Solid State Materials


Published in journal(s) :

Advanced Materials Research

AdvancedMaterials Research Vols. 1-2 (1994) pp. 201-208
@ 1994 Scitec Publications, Switzerland

Keywords : Hexagonal Holmium Orthophosphate-synthesis, Characterization, Rietveld Analysis


A new hexagonal rhabdophane-type holmium phosphate has been synthesized in basic medium (pH = 12.5) from aqueous solutions of holmium nitrate and potassium phosphate, with K/Ho = 12. The compound has been characterized by X-ray diffraction and chemical analysis. The best crystallinity is obtained when the compound was calcinated at 700 °C for 24h in which the K percent was determined to be 9.7 % (Wt). A Rietveld analysis indicated that this compound formula is HoPO4,0.072 KOH corresponding to a K percent of 1 %, the residual potassium remains in an amorphous phosphate. The two amorphous + hexagonal forms gradually transform into azircon-type HoPO4 phase, between 750 and 1200 °C.