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_analytical.chemical_species

Name:
_atom_analytical.chemical_species

Definition:

   
    Chemical formula of the species to which the corresponding
    _atom_analytical.chemical_species_mass_percent refers.

    The following rules apply in the construction of the formula:

    1. Only recognized element symbols may be used.

    2. The first element corresponds to the analyte. The remaining
   elements should be given in alphabetical order by symbol.

    3. Each element symbol is followed by a 'count' number. A count of
   '1' may be omitted.

    4. A space or parenthesis must separate each cluster of (element
   symbol + count). A formula cannot begin with a parenthesis.

    5. Where a group of elements is enclosed in parentheses, the
   multiplier for the group must follow the closing parentheses.
   That is, all element and group multipliers are assumed to be
   printed as subscripted numbers.

Examples:

'Fe2 O3'
Li
'Si O2'
'Ca S O4 (H2 O)2'

Type: Text

Category:
atom_analytical








































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