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: RGB - enamel _database_code_amcsd 0002293 9.4506 9.4506 6.8780 90 90 120 P6_3/m atom x y z occ Ca1 2/3 1/3 .0021 .97 Na1 2/3 1/3 .0021 .02 Mg1 2/3 1/3 .0021 .01 Ca2 .2464 .9907 .25 .94 Na2 .2464 .9907 .25 .02 Mg2 .2464 .9907 .25 .01 P .3992 .3692 .25 .95 O1 .3322 .4864 .25 .94 O2 .5802 .4608 .25 .97 O3 .3399 .2565 .0697 .92 Oh 0 0 .1851 .51 H 0 0 .0608