Calcium deficient apatites, which could be used as precursors of the i
norganic component of biological apatites, have been synthesised by co
ntrolled crystallisation. The influence of the pH and the reaction tim
e in the calcium deficiency and the crystal size of samples have been
studied. For determination of Ca/P ratio of as-received apatites, a me
thod based on Rietveld profile analysis of X-ray diffraction data is p
roposed. The results obtained using this method agree well with those
obtained by other classical analytical methods.