How the R factor changes as molecules become larger

The R factors and the numbers of independent atoms for the entire set of mo lecular organic structures contained in the Cambridge Structural Database w ere retrieved and analysed. The average R factor for all structures contain ing the same number of independent atoms was plotted against the number of independent atoms. A clear correlation was observed. The plot is suggested to give a graphical overview of how values of the R factor for large-molecu le structures with 200-1000 independent atoms increase as the number of ind ependent atoms increases. (C) 2000 International Union of Crystallography P rinted in Great Britain - all rights reserved.