Crystallization of Cs, Sr and selected rare earth ions in apatite phosphate structure was investigated. Compounds of the formula CsLaSr3(PO4)(3)OH (CSOH), CsLaSr3(PO4)(3)F (CSF) and the simulated waste forms of the compositions CsLa0.8Nd0.1Sm0.1Sr3(PO4)(3)OH (CNSOH) and CsLa0.7Nd0.1Sm0.1Eu0.1Sr3(PO4)(3)F (CNSEF) were synthesized and characterized by powder XRD, TGA and SEM techniques. The leachability behaviour of the single phases was studied for a period of one month by MCC-5 test using powder specimen. The leachability of Cs and other rare earth ions was found to be negligible. The leach rates (LRi) of Sr and P were observed as follows: CSOH - LRSr = 10(-3)-10(-4) g/m(2)/d, LRP = 10(-4) g/m(2)/d; CSF - LRSr = 10(-3) - 10(-5) g/m(2)/d, LRP = 10(-4)-10(-5) g/m(2)/d; CNSOH and CNSEF - LRSr = 10(-3)-10(-4) g/m(2)/d, LRP = 10(-4)-10(-5) g/m(2)/d. (c) 2012 Elsevier Ltd. All rights reserved.