Fluorapatite Hughes J M, Cameron M, Crowley K D American Mineralogist 76 (1991) 1857-1862 Ordering of divalent cations in the apatite structure: Crystal structure refinements of natural Mn- and Sr-bearing apatite sample Mn1.21 _database_code_amcsd 0001423 9.3430 9.3430 6.8227 90 90 120 P6_3/m atom x y z occ Biso Ca1 2/3 1/3 .0021 .795 .947 Mn1 2/3 1/3 .0021 .205 .947 Ca2 -.00708 .24157 .25 .935 .751 Mn2 -.00708 .24157 .25 .065 .751 P .36997 .39878 .25 .71 O1 .4883 .3298 .25 1.19 O2 .4656 .5882 .25 2.01 O3 .2581 .3406 .0702 1.87 F 0 0 .25 .740 2.31