New structure

The new structure of a molecule is specified in a .MOL ascii file. File format details are described here. Usually the data needed to define a structure are not typed in explicitly. Rather, they are imported from the Inorganic Crystal Database, the Cambridge Structural Database, the Protein Data Bank, from the geometry optimization output file of Gaussian-98 or the crystal geometry optimization  CRYSTAL03 output file.

If the structural information are taken from books or papers the user can use any text editor to set up the .MOL file. As explained in the File format section the minimal data are, the TITLE, the CELL parameters and the COORD records, the latter reporting the fractional coordinates of atoms belonging to the asymmetric unit for the given structure. In the most recent publications, the coordinates are provided as a Crystallographic Interchange Format (CIF) file which can be easily imported in MOLDRAW.

From the CELL record MOLDRAW automatically determines the crystal lattice. The user can then choose the space group symbol from the provided list by the

(Crystal--->Select a space group...) menu. Automatically MOLDRAW will provide only the space groups which are compatible with the lattice symmetry (i.e. for a triclinic lattice only P1 and P-1 are available).

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