Calcite Markgraf S A, Reeder R J American Mineralogist 70 (1985) 590-600 High-temperature structure refinements of calcite and magnesite Sample: T = 600 C _database_code_amcsd 0000987 4.978 4.978 17.354 90 90 120 R-3c atom x y z B(1,1) B(2,2) B(3,3) B(1,2) B(1,3) B(2,3) Ca 0 0 0 .0382 .0382 .00243 .0191 0 0 C 0 0 .25 .0356 .0356 .0021 .0178 0 0 O .2547 0 .25 .043 .079 .0050 .0395 -.00395 -.0079