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Core CIF Dictionary version 2.3

_atom_site_aniso_B_

Names

'_atom_site_aniso_B_11' '_atom_site_aniso_B_12' '_atom_site_aniso_B_13' '_atom_site_aniso_B_22' '_atom_site_aniso_B_23' '_atom_site_aniso_B_33'

Category: atom_site

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

Must appear in a looped list containing '_atom_site_aniso_label'

Related item: '_atom_site_aniso_U_'
Related function: conversion

Units: A^2^ ( angstroms squared)

Definition

    	
   These are the standard anisotropic atomic displacement
   components in angstroms squared which appear in the structure
   factor term:

   T = exp{-1/4 sum~i~ [ sum~j~ (B^ij^ h~i~ h~j~ a*~i~ a*~j~) ] }

   h = the Miller indices
   a* = the reciprocal-space cell lengths

   The unique elements of the real symmetric matrix are
   entered by row.

   The IUCr Commission on Nomenclature recommends against the use
   of B for reporting atomic displacement parameters. U, being
   directly proportional to B, is preferred.
 


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