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: RHB - enamel _database_code_amcsd 0002295 9.4616 9.4616 6.8819 90 90 120 P6_3/m atom x y z occ Ca1 2/3 1/3 .0015 .97 Na1 2/3 1/3 .0015 .02 Mg1 2/3 1/3 .0015 .01 Ca2 .2476 .9914 .25 .93 Na2 .2476 .9914 .25 .02 P .3999 .3693 .25 .95 O1 .3301 .4847 .25 .94 O2 .5796 .4590 .25 .96 O3 .3436 .2592 .0706 .93 Oh 0 0 .1771 .54 H 0 0 .0608 .55