data_40107-ICSD
#?2009 by Fachinformationszentrum Karlsruhe, and the U.S. Secretary of
#Commerce on behalf of the United States. All rights reserved.
_database_code_ICSD 40107
_audit_creation_date 1998/06/26
_audit_update_record 2007/04/01
_chemical_name_systematic 'Calcium Carbonate'
_chemical_formula_structural 'Ca (C O3)'
_chemical_formula_sum 'C1 Ca1 O3'
_chemical_name_mineral Calcite
Ca1 Ca2+ 6 b 0 0 0 1. 0
C1 C4+ 6 a 0 0 0.25 1. 0
O1 O2- 18 e 0.2567(2) 0 0.25 1. 0
最后一行里的0.2567(2)是什么意思 (2)表示的是什么。谢谢。