PLATON is designed for the automated generation of a variety of geometrical entities such as bond distances, bond angles, torsion angles, least-squares planes and ring-puckering parameters, see an introductory example. All derived parameters are accompanied by standard deviations that are calculated by numerical methods from the supplied standard deviations in the primary input parameters.
The free format input data generally consist of two types of data that are normally but not necessarily supplied separately to the program. The crystallographic or molecular data such as coordinates, thermal parameters, cell dimensions and symmetry, possibly generated by the structure determination or refinement program, are read from an automatically created SPF file. Instructions may entered directly from the keyboard into the PLATON dialog Window (called up from the menu item PLATON command. Alternatively a graphical menu interface (from PLATON menu) is also available.
In general only global instructions are necessary to obtain tables of the required derived molecular geometry data. Specific information such as atomic radii and other properties related with the element types involved are by default drawn from internal tables. The simple instruction CALC will automatically execute virtually all calculations that are of interest for the supplied parameter set.
The set of available analysis procedures includes those for rigid-body thermal motion with bond distance correction, puckering analysis (including the Cremer and Pople variety),hydrogen bonds (including an analysis in terms of networks), voids in the structure and five-coordination (Berry pseudorotation). Appropriate references to the literature are given in the output listing.
The calculations are complemented with graphics facilities such as thermal motion ellipsoid plots, Newman projection plots, space-filling plots and projection plots of the structure on the various least-squares and ring planes.
For a recent (2-Feb-98) overview of PLATON click here .