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Core CIF Dictionary version 2.3

_atom_site_U_equiv_geom_mean

Name

'_atom_site_U_equiv_geom_mean'

Category: atom_site

Data type: numb (with optional s.u. in parentheses)

Must appear in a looped list containing '_atom_site_label'

Enumeration range: 0.0 -> infinity

Related item(s), related function(s):
'_atom_site_U_iso_or_equiv' alternate '_atom_site_B_equiv_geom_mean' conversion

Units: A^2^ ( angstroms squared)

Definition

    	
   Equivalent isotropic atomic displacement parameter, U(equiv),
   in angstroms squared, calculated as the geometric mean of
   the anisotropic atomic displacement parameters.

   U(equiv) = (U~i~ U~j~ U~k~)^1/3^

   U~n~  = the principal components of the orthogonalised U^ij^
 


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