International
Tables for
Crystallography
Volume G
Definition and exchange of crystallographic data
Edited by J. R. Hester and B. McMahon

International Tables for Crystallography (2026). Vol. G. Early view chapter
https://doi.org/10.1107/97809553602060001011

Chapter 4.2 Core dictionary (coreCIF)


Index

Core dictionary version 3.3.0

_atom_site.label

Name:
_atom_site.label

Aliases:

_atom_site_label
_atom_site.id

Definition:

   
     This label is a unique identifier for a particular site in the
     asymmetric unit of the crystal unit cell. It is made up of
     components, _atom_site.label_component_0 to *_6, which may be
     specified as separate data items. Component 0 usually matches one
     of the specified _atom_type.symbol codes. This is not mandatory
     if an _atom_site.type_symbol item is included in the atom site
     list. The _atom_site.type_symbol always takes precedence over
     an _atom_site.label in the identification of the atom type. The
     label components 1 to 6 are optional, and normally only
     components 0 and 1 are used. Note that components 0 and 1 are
     concatenated, while all other components, if specified, are
     separated by an underline character. Underline separators are
     only used if higher-order components exist. If an intermediate
     component is not used it may be omitted provided the underline
     separators are inserted. For example the label 'C233__ggg' is
     acceptable and represents the components C, 233, '', and ggg.
     Each label may have a different number of components.

Examples:

C12
Ca3g28
Fe3+17
H*251
C_a_phe_83_a_0
Zn_Zn_301_A_0

Type: Word

Category:
atom_site








































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