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: RGP - enamel _database_code_amcsd 0002292 9.4554 9.4554 6.8835 90 90 120 P6_3/m atom x y z occ Ca1 2/3 1/3 .0026 .97 Na1 2/3 1/3 .0026 .02 Mg1 2/3 1/3 .0026 .01 Ca2 .2471 .9909 .25 .94 Na2 .2471 .9909 .25 .02 P .3996 .3692 .25 .94 O1 .3311 .4857 .25 .93 O2 .5805 .4599 .25 .98 O3 .3408 .2577 .0718 .91 Oh 0 0 .1818 .53 H 0 0 .0608 .81