checkCIF procedure

PLAT068

 In the ideal case, both data items should have the same value. If not, 
 the reason should be clear. A reason might be that population parameter values
 are archived by SHELXL with only two decimals in the CIF.
 NOTE: SHELXL counts the number of electrons in the unit-cell. The result   
 will in general be an integer. This is also the number checked for here.   
 The official definition calls for 'The effective number of electrons in the
 crystal unit-cell contributing to F(000)'. It 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