Bonds snap to chemistry
New bonds land on real bond angles: 120° zigzags, linear triple bonds and allenes, the free side of a ring atom. Rings fuse onto the bond you point at.
Draw structures without a ChemDraw licence
Covalent is a free structure editor that runs in any modern browser, including Chromebooks and tablets. It checks the chemistry while you draw, puts structures, text and arrows on pages for worksheets, exams, schemes and group meetings, and opens ChemDraw's CDXML files.
ChemDraw and Covalent side by side
| What you need | ChemDraw | Covalent |
|---|---|---|
| Price | Paid licence | Free |
| Installation | Windows or macOS program | None, runs in the browser |
| Chromebook, Linux, tablet | No | Yes |
| Account needed | Licence activation | No |
| Bond, ring and chain tools | Yes | Yes |
| Wedged and hashed bonds | Yes | Yes |
| Charges and element hotkeys | Yes | Yes |
| Valence check while drawing | Warns after drawing | Refuses as you draw |
| Clean up a drawing | Yes | Yes |
| Paste SMILES or a MOL block | Yes | Yes |
| Export MOL, SVG and PNG | Yes | Yes |
| Insert a compound by name | Yes | From a 48,000-compound database |
| Reaction arrows and conditions | Yes | With reaction SMILES and RXN files |
| Curved and fishhook mechanism arrows | Yes | On the page |
| Several structures, text and shapes on a page | Yes | Yes |
| ACS Document 1996 style | Yes | Plus classroom and group-meeting styles |
| Templates | Template files to buy or build | Worksheet, exam, reaction scheme, group meeting |
| PDF and print | Yes | Yes |
| Paste into Google Docs or Word | Word on Windows and macOS | Yes |
| Structure to IUPAC name | Yes | Shows the name for catalogued compounds |
| NMR prediction | ChemNMR add-on | Separate NMR predictor |
| Open ChemDraw files | Yes | CDXML, with schemes and text; CDX not yet |
ChemDraw is the long-established reference for publication graphics, and it still does more: orbitals, TLC plates, glassware, CDX files and decades of journal styles. Covalent covers what a class or a group meeting needs, for free, on any device.
What Covalent does differently
Impossible structures are refused
A fifth bond to carbon or a double bond to a saturated nitrogen is stopped as you draw, with a plain explanation, instead of producing a structure no chemist can make.
Stereochemistry that round-trips
Wedges and hashes are read the way RDKit and the InChI library read them, and a structure opened from SMILES comes back with its stereocentres drawn.
Every compound in the database
Insert any of 48,000 compounds by name, CAS number or formula, or paste SMILES or a MOL block straight onto the canvas.
Whole documents, not just drawings
Lay out structures, text, arrows and answer lines on pages, start from a worksheet, exam, reaction scheme or group-meeting template, switch the whole document to ACS 1996 and download a PDF or paste it into Google Docs.