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: RFP - enamel _database_code_amcsd 0002290 9.4592 9.4592 6.8816 90 90 120 P6_3/m atom x y z occ Ca1 2/3 1/3 .0007 .97 Na1 2/3 1/3 .0007 .02 Mg1 2/3 1/3 .0007 .01 Ca2 .2463 .9893 .25 .92 Na2 .2463 .9893 .25 .02 P .3998 .3688 .25 .91 O1 .3286 .4869 .25 .91 O2 .5772 .4558 .25 .95 O3 .3444 .2599 .0716 .92 Oh 0 0 .1748 .55 H 0 0 .0608 .62