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: H6L, synthetic _database_code_amcsd 0002281 9.4081 9.4081 6.8887 90 90 120 P6_3/m atom x y z occ Ca1 2/3 1/3 .0007 Ca2 .2426 .9904 .25 P .3948 .3657 .25 O1 .3270 .4849 .25 O2 .5791 .4618 .25 O3 .3417 .2578 .0711 Oh 0 0 .1837 .5 H 0 0 .0608 .5