Calcite Antao S M, Hassan I The Canadian Mineralogist 48 (2010) 1225-1236 Temperature dependence of the structural parameters in the transformation of aragonite to calcite, as determined from in situ synchrotron powder X-ray-diffraction data Locality: Cuenca, Spain Note: T = 681 C Note: P = 101 kPa _database_code_amcsd 0017868 4.9759 4.9759 17.4486 90 90 120 R-3c atom x y z Uiso Ca 0 0 0 .0419 C 0 0 .25 .074 O1 .2492 0 .25 .074