Hydroxylapatite Wilson R M, Elliot J C, Dowker S E P American Mineralogist 84 (1999) 1406-1414 Rietveld refinement of the crystallographic structure of human dental enamel apatites Sample: RE1 - enamel _database_code_amcsd 0002288 9.4564 9.4564 6.8821 90 90 120 P6_3/m atom x y z occ Ca1 2/3 1/3 .0041 .97 Na1 2/3 1/3 .0041 .02 Mg1 2/3 1/3 .0041 .01 Ca2 .2437 .9888 .25 .93 Na2 .2437 .9888 .25 .02 P .3969 .3669 .25 .93 O1 .3317 .4902 .25 .87 O2 .5739 .4562 .25 .98 O3 .3398 .2567 .0693 .87 Oh 0 0 .1857 .52 H 0 0 .0608 .88