Fluoride ion-promoted reaction of beta-tricalcium phosphate to fluoridatedhydroxyapatite

Solvothermal reaction of beta -tricalcium phosphate (beta -TCP) [Ca-3(PO4)( 2)] with ammonium fluoride in water-1-octanol biphase proceeds to afford fl uoridated hydroxyapatite (FRAp) [Ca-10(PO4)(6)(OH)(2(1-x))F-2x] quantitativ ely. It was found that FHAps with various fluoride contents were more easil y prepared under mild reaction conditions and that higher crystallinity of FHAp was obtained, compared with the reaction of alpha -TCP with fluoride i ons. The solvolysis reaction of beta -TCP did not proceed without fluoride ions, whereas the reaction of alpha -TCP proceeded with or without fluroide ions. This indicates that the former reaction is promoted by fluoride ions . (C) 2001 Elsevier Science B.V. All rights reserved.