BKChem is a multiplatform vector drawing application that lets you create a representation of the chemical bonds that form a fixed material.
This is a series of templates to make your task easy. Some chemical compounds, such as benzene and purina, are already built in model BKChem, so you do not always have to start from scratch.
You will draw the bonds one by one. To ease the scammmatics, limit each bond's length and angle. BKChem supports the use of linear formulas, charges, and radicals.
You can export your work as an SVG, ODF, PNG, PDF or Open Office file among others.