Synthesis and Characterization of New Apatite-Related Phosphates

New phosphates of the formula M3+M2+4(PO4)3O (M3+=Bi and La; M2+=Ca and Sr) are synthesized. The compounds are isostructural with bismuth calcium vanadate, BiCa4(VO4)3O. A nonlinear increase in both the a and c lattice parameters with an increase in strontium content in the solid solution BiCa4-xSrx(PO4)3O (x=1–4) is observed. The compounds are characterized by infrared spectroscopy.