David: My late response to your comcifs mail of Oct 15 is indicative of how far behind I am with my non-urgent correspondence... and for this I apologise. Phillip Fanwick's views would certainly be typical of structural scientists not involved in macromolecular work. "Theta max" clearly means a lot more in this field than "d min", as indeed does the max sin(theta)/lambda (s), which is also radiation independent. It would be just as informative to cite max s as min d for these purposes.... and quite frankly I believe that setting the expected data limit in the Acta C Notes for Authors at an s of 0.6 is just as intuitive as setting it at a d min of 0.83. Just as with the adp's its likely that the micro and macro crystallographers will continue to use the measures of most convenience until the distinctions between the techniques become blurred and disappear. In the meantime the CIF dictionaries will need to provide the methods that enable these conversions to be done effortlessly and perhaps automatically. Cheers, Syd.
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