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. 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 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.