The program system MOLGEN is devoted to the computation of all structural formulae (= connectivity isomers) that correspond to a prescribed molecular formula together with optional further conditions (e.g. prescribed and forbidden substructures). MOLGEN provides an efficient, portable and inexpensive tool for molecular structure elucidation in science and education.

The system consists of several components:

• a generator for connectivity isomers

• a graphical molecule editor and 2D-display

• a display for 3D-placements using an energy optimization, and

• a generator for all configurational isomers.