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_aniso.B_13

Name:
_atom_site_aniso.B_13

Aliases:

_atom_site_aniso_B_13
_atom_site.aniso_B[1][3]
_atom_site_anisotrop.B[1][3]

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.

     Note that U^ij^ = β^ij^/(2 π^2^ a*~i~ a*~j~) = B^ij^/(8 π^2^).

     Ref: Trueblood, K. N. et al. (1996). Acta Cryst. A52, 770-781.

Type: Real

Units: angstrom_squared

Category:
atom_site_aniso








































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