Chemistry

The chemical structure editor draws molecules for electronic lab notebooks, compound registration and LIMS. Draw with the mouse, a pen or the keyboard: atoms of any element, single, double, triple and wedged bonds, chains, rings, charges and groups such as OMe or Boc. The formula, the average weight and the exact mass follow every change, and a drawing that breaks the rules of valence is marked where it goes wrong.

It reads and writes SMILES, molfiles (V2000 and V3000) and SD files, gives one canonical SMILES per structure however it was drawn, labels stereocentres R or S and double bonds E or Z, and lays a rough drawing out again without losing its stereochemistry. An SD file opens as records to step through and to search for a substructure; a reaction arrow turns a drawing into a reaction.

Try it with your own molfiles and SD files in confidence: they are opened by your browser, on your device. Nothing is uploaded, no copy reaches us or anyone else, and nothing is kept once you close this tab.

Draw, check and register a structure

A made-up registration form for a reference sample of (S)-ibuprofen, drawn by hand and a little untidy. The chemistry is real; the registry number, project, notebook and chemist are invented. Fill in the form from the drawing, then load a mistyped version and see the check find it.

Formula, weight and exact mass Canonical SMILES R/S and E/Z labels Clean the layout Load a mistyped copy and check it Show the molfile (V3000) Start again
Registry number
KX-004127 (pending)
Project
Larkspur - reference standards
Notebook
ELN-2026-0318, page 42
Submitted by
R. Ashworth, 24 October 2026
Formula
-
Weight
-
Canonical SMILES
-
Stereochemistry
-
Keyboard: the arrow keys move between atoms and bonds. On an atom, a letter changes the element (l for Cl, b for Br), 1, 2 or 3 adds a bond, + and - change the charge and Enter types a label such as OMe. On a bond, 1, 2 or 3 sets the order and w the wedge. Ctrl+Z undoes.