Greenish-yellow emitting microcrystalline Ca6Ba(PO4)(4)O:Eu2+ phosphor was successfully prepared by a solution-precipitation assisted high temperature reaction method. Phase structure, morphology and/or luminescence properties of the precursor and the as-prepared phosphors were characterized. The phase-pure Ca6Ba(PO4)(4)O:Eu2+ phosphors were obtained with smooth grain surface and particle size of 2-8 mu m. Ca5Ba(PO4)(4)O:Eu2+ exhibits bright greenish-yellow color emission with its maximum at 540 nm upon UV-blue light excitation. The maximum position of the broad emission band is independent on the calcination temperature. The emission intensity increases with increasing calcination temperature due to improved crystallinity. Besides, the presence of two Eu2+ emission centers in the Ca6Ba(PO4)(4)O crystal lattice was confirmed and the coordination effects are considered concerning the roles of isolated O atoms and those from the PO4 tetrahedra. (C) 2015 Elsevier Ltd. All rights reserved.