Chemboy is an application to do basic chemistry calculations. It was born out of the memory of a chemistry class which assigned large numbers of problems which could be solved by doing the same tedious calculation over and over again. For example, suppose that you wanted to know the mass of 2.8 mol of methane (C H4). You could figure that since the atomic weight of carbon was 12.011 g/mol (tediously looking it up in the periodic table) and the atomic weight of hydrogen was 1.00794 g/mol (or about 1 g/mol), and there were four hydrogens, the formula weight of C H4 was 12.011+4*1.00794 = 16.042759 g/mol, and multiply this by 2.8 to get the final answer.

That's a lot of work. So, with Chemboy, you can simplify most parts of that process. To save yourself the trouble of looking in the periodic table, you can type "c" and "h" to look up carbon and hydrogen. (You could also type "carbon" and "hydrogen", or even their atomic numbers, but why would you want to?) You can type "C H4" (or "c h4"---Chemboy isn't case sensitive) to get the formula weight of methane. Or you could just ask Chemboy for the final answer from the beginning by typing "2.8 mol C H4", to which it would reply "2.8 mol of C H4, 44.919724 g, 62.77467 L at STP". See how much time this could save?

Chemboy can also speed up use of Boyle's Law, Charles' Law, the Combined gas Law, and the Ideal gas Law. Chemboy does the equivalent of solving all the equations for you behind the scenes (the specific technique is kind of cool, but beyond the scope of this description).

Basic text-based usage

To quit, type "quit" or "bye". To see the help message, type "help" or "?". If you want to find out how many moles and liters are in 12 milligrams of diatomic hydrogen, type "12 mg H2". If you want to find out about the element Krypton, type either "Krypton", "krypton", "Kr", or "36" (the atomic number of Krypton). If you want to find out the formula weight of methane, type in the formula with spaces between elements, like this: "C H4". The same goes for things like glucose, "C6 H12 O6". To use laws like the Ideal gas law and the Combined gas law, type in "law" and choose a law. There are short commands for the individual laws: "charles", "boyle", "idealgas", and "combinedgas".


Chemboy can run just about anywhere in some form or another. If you're on Windows, you should probably download the installer for Windows.

There are three interfaces. First, and most widely useful, is the text-based interface. This will run anywhere. It presents you with a simple prompt at which you can type queries. It is perfectly usable, and the only thing wrong with it is that some people are oddly biased against anything that resembles a command line.

The second interface is based on Ltk. It requires Tcl/tk, and should run well on Linux, Mac OS X, and Windows---but don't count on Windows. It doesn't support the laws (ideal gas law, etc.), but it can do the rest fairly well. It is still rough and unfinished.

Finally, for those of you lucky enough to use LispWorks, there is a CAPI-based GUI. This GUI looks snazzy on Linux, and it's fully featured on any OS, but it looks utterly lousy on Windows (I haven't tested it on Mac OSX). So I repeat my mantra: don't count on Windows.

Chemboy is ANSI Common Lisp, and should run on any Common Lisp implementation. That said, you can't tell until you test. Chemboy has been tested on:

Corman Lisp requires a little extra setting up, but that's the price you pay for using the youngest and least ANSI-compliant (but very useful) Common Lisp out there.

Starting it

To start the text interface, call (chemboy-text:chemboy-repl).

To start the Ltk interface, load gui.lisp in the Chemboy source distribution and call (chemboy-gui:run-chemboy-gui).

To start the CAPI interface, load capi-gui.lisp in the Chemboy source didstribution and call: (capi:display (make-instance 'capi-gui::chemboy-capi-gui))

Home page

There is a project page with mailing lists and download links. The license is the LLGPL. Chemboy was created by Peter Scott.