Chemtool is a free, open-source GTK+ tool for drawing 2D chemical structures on Linux. See features, export formats, and how it compares to modern alternatives.
Chemtool is a purpose-built drawing tool for organic chemistry notation, not a general vector graphics editor repurposed for chemistry. Its canvas supports square and hexagonal alignment grids, multiple zoom levels, and a wide set of chemistry-specific bond types, including wedge, dashed wedge, double, triple, quadruple, wavy, and wide bonds, which together cover most of what a student or researcher needs to represent standard organic structures accurately.
Once a structure is drawn, Chemtool can export it to a range of formats, including PNG, SVG, EPS, XFig, PicTeX, and X bitmap, as well as import and export the MDL molfile format and import Protein Data Bank (PDB) files. A bundled helper utility, cht, calculates the molecular formula and exact molecular weight of a drawing or a selected fragment, a small but genuinely useful feature for coursework and quick reference.
Because Chemtool is packaged directly in the repositories of most major Linux distributions, many users encounter it simply by searching their distro's package manager for a chemical structure editor rather than actively seeking it out online. Its GPL license and minimal system requirements have kept it alive and installable for years even as development activity around the core project has slowed.
Compared with actively maintained modern alternatives, such as the commercial ChemDraw, or free web-based tools like Ketcher and MarvinSketch, Chemtool's interface and feature set look dated: there is no cloud collaboration, no 3D structure visualization, and no reaction-mechanism tooling. What it does offer is a lightweight, fast, completely free, and Linux-native way to produce clean 2D structure diagrams, which is exactly the niche it continues to fill for students, educators, and hobbyists working on Linux.
Yes, Chemtool is free and open source, released under the GNU General Public License.
Chemtool runs on Linux and other X11-based Unix-like systems; it does not have a native Windows, macOS, or web version.
Chemtool was originally written by Thomas Volk, a German chemistry and biology student, and has since been maintained by other contributors.
Chemtool can export to PNG, SVG, EPS, XFig, PicTeX, X bitmap, and the MDL molfile format.
Yes, via its built-in cht helper utility, which computes the sum formula and exact molecular weight of a structure or fragment.
Development has slowed significantly in recent years; it functions today as a stable, installable legacy tool rather than a frequently updated product.
Commercial and web-based alternatives include ChemDraw, Ketcher, MarvinSketch, and BKChem.
Usually not. Chemtool is packaged in the repositories of most major Linux distributions and can typically be installed directly through the package manager.