Distribution of Eu3+ ions in whitlockite-type Ca3-xEu2x/3(PO4)2 orthophosphates

A crystal chemical investigation of the Ca3(PO4)2-EuPO4 system has pointed out the existence of a continuous solid solution of formulation Ca3-xEu2x/3(PO4)2 (0 ≤ x ≤ 3/7) and of whitlockite-type structure. The lattice evolution has been analyzed by X-ray diffraction and emission spectroscopy, the Eu3+ ion being used as local probe. The cell parameter a as well as the volume of the unit cell increase with x, but no significant modification of the emission spectra has been observed. These results are discussed on the base of crystal chemical considerations