[Thermal stability of carbonates in bone tissue].

The analysis shows that carbonate ions present in the mineral phases of calcified tissues are decomposed in two steps during their ignition. These carbonate ions might be all localised in the phosphate sites of the apatitic structure (B type carbonate apatite). The loss of one important part of carbonate ions at a abnormally low temperature (250 degrees C) might result from an intracristalline reaction between these ions and HPO4(2-) or P2O7(4-) ions present in the apatitic structure.