Core dictionary (coreCIF) version 2.4.5




   The expression for a structure factor evaluated in the
   zeroth-order case h = k = l = 0, F(000). This may contain
   dispersion contributions and is calculated as

   F(000) = [ (sum f~r~)^2^ + (sum f~i~)^2^ ]^1/2^

   f~r~   = real part of the scattering factors at theta = 0
   f~i~   = imaginary part of the scattering factors at theta = 0

            the sum is taken over each atom in the unit cell

   For X-rays, non-dispersive F(000) is a positive number
   and counts the effective number of electrons in the unit cell;
   for neutrons, non-dispersive F(000) (which may be negative)
   counts the total nuclear scattering power in the unit cell. See

May appear in list containing _exptl_crystal_id

Type: numb

Category: exptl_crystal