Index

Core dictionary version 3.0.14

_atom_site.B_iso_or_equiv

Definition:

   
     Isotropic atomic displacement parameter, or equivalent isotropic
     atomic displacement parameter, B(equiv), in angstroms squared,
     calculated from anisotropic temperature factor parameters.
 
     B(equiv) = (1/3) sum~i~[sum~j~(B^ij^ a*~i~ a*~j~ a~i~ a~j~)]
 
     a     = the real-space cell lengths
     a*    = the reciprocal-space cell lengths
     B^ij^ = 8 pi^2^ U^ij^
     Ref: Fischer, R. X. & Tillmanns, E. (1988). Acta Cryst. C44, 775-776.
 
     The IUCr Commission on Nomenclature recommends against the use
     of B for reporting atomic displacement parameters. U, being
     directly proportional to B, is preferred.

Type: Real

Units: angstrom_squared

Category:
atom_site