Every now and then, students need a tool for chemistry classes that makes it easy to put chemical structural formulas on digital paper. This not only makes it easier to work on homework but also helps to document experiments by drawing the chemical reactions. The free molecule editor JChemPaint [1] supports the (budding) chemist here.

The LGPL Java program is only available from the package sources of a few distributions. Arch Linux maintains the program in the Arch User Repository, but JChemPaint can easily be downloaded from the homepage and run at the command line (Listing 1). The settings let you change the language and appearance of the application, among other things. To do this, select Edit | Settings and switch to the Other settings tab.

Drawing Molecules

There are two different ways to create drawings in JChemPaint. To represent a chemical compound as a structural formula, you would start with a central atom such as carbon. Alternatively, you can start from the edge of the structural formula. For carbonic acid, for example, first draw the functional group (a small collection of atoms that determines how a molecule works), that is, carboxylic acid R-C=O-OH. Click on the C icon in the lower toolbar and then on the drawing board to transfer the carbon atom to the drawing area.

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