Calcite Prencipe M, Pascale F, Zicovich-Wilson C M, Saunders V R, Orlando R, Dovesi R Physics and Chemistry of Minerals 31 (2004) 559-564 The vibrational spectrum of calcite (CaCO3): an ab initio quantum-mechanical calculation Note: Theoretically derived structure _database_code_amcsd 0008879 5.0492 5.0492 17.3430 90 90 120 R-3c atom x y z Ca 0 0 0 C 0 0 .25 O .25642 0 .25