MISSYM1.1 – a flexible new release

Version 1.1 of MISSYM is now available and the following new features have been added: a HELP facility to guide and caution the user; the input of a distance tolerance for axes and planes, and a separate tolerance for inversion centers and translations; the possibility of flagging atomic positions as `possibly disordered'; the possibility of allowing for errors in assigning chemical types; the possibility to extract the symmetry for a single atom type; the option to run from sensible default values. This version is more flexible than, but not quite as fast as, the original. Only one-third of structures require the full application of MISSYM because simple conditions, simultaneously satisfied by about two-thirds of the structures published recently, rule out the possibility of extra symmetry in the model. The existence of an efficient computer program for flagging the cases of overlooked symmetry should not give a false sense of security or be used to justify short cuts in the preliminary study of crystal symmetry.