Core dictionary (coreCIF) version 2.3.1




   Isotropic atomic displacement parameter, or equivalent isotropic
   atomic  displacement parameter, U(equiv), in angstroms squared,
   calculated from anisotropic atomic displacement  parameters.

   U(equiv) = (1/3) sum~i~[sum~j~(U^ij^ a*~i~ a*~j~ a~i~ a~j~)]

   a     = the real-space cell lengths
   a*    = the reciprocal-space cell lengths

   Ref: Fischer, R. X. & Tillmanns, E. (1988). Acta Cryst. C44,

Appears in list containing _atom_site_label

The permitted range is 0.0 -> infinity

Related items : _atom_site_U_equiv_geom_mean



Type: numb

Category: atom_site

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