Structural study of Yb3＋, Eu3＋ and Pr3＋ doped Ca9Lu（PO4）7

The whitlockite-like crystal structure of Ca9Lu(PO4)7 when doped with several ions(Yb3+, Eu3+ and Pr3+) at different concentrations(1 mol.%, 5 mol.% and 10 mol.%) was studied, by means of synchrotron X-ray diffraction. In particular for Eu3+ and Pr3+, the presence of the dopant ion significantly changed the occupation factors(OF’s) of the Ca2+ and Lu3+ cations and gave rise to a distortion of the metal-oxygen polyhedra. The observed structural features clearly showed significant impact of the dopant ion on the crystal structure of the host.