Calcite Markgraf S A, Reeder R J American Mineralogist 70 (1985) 590-600 High-temperature structure refinements of calcite and magnesite Sample: T = 400 C _database_code_amcsd 0000986 4.980 4.980 17.224 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 .0269 .0269 .0023 .01345 0 0 C 0 0 .25 .023 .023 .0022 .0115 0 0 O .2558 0 .25 .031 .058 .0041 .029 -.00255 -.0051