Carbonate in Hydroxylapatite.
Unit cell dimensions of hydroxylapatite synthesized hydrothermally are a(0) = 9.42(6) A and c(0) = 6.88(5) A, whereas carbonate apatite (2.29 CO(2)) gave a(0) = 9.43(6) A and c(0) = 6.88(5) A. A deficiency of both calcium and phosphorus in the carbonate apatite suggests a coupled substitution of hydronium and carbonate ions in the structure.
Simpson
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