View CDX files in your browser
How chemists' drawings travel between papers, theses and lab notebooks. Open a CDX right here, drawn as ChemDraw drew it, with no ChemDraw. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your drawing opens as ChemDraw laid it out on white paper, every structure, arrow, bracket and text where it was put.
- Skeletal formulas • Wedges, hashes and a ring's double bonds inside it
- Pick an atom • Its element, hydrogens and charge
- Each molecule's formula • And its weight
- Export • Save as SVG, PNG, MOL or PDF
About CDX
ChemDraw, written in 1985 by David Evans and Stewart Rubenstein and sold by CambridgeSoft, is the app chemists draw structures and reactions in, and CDX is its own binary file. Journals ask for figures in it, supporting information comes with it, and every structure in a thesis or an electronic lab notebook has usually been one.
A CDX is a tree of tagged objects: a page holds fragments of atoms and bonds, texts, reaction arrows, brackets, curves and shapes, each with its place in points and its style, like a bond's wedge or hash, an atom's charge or isotope and a label's font. CambridgeSoft published the format, and CDXML writes the same objects as XML.
Filepeek reads it in your browser and draws the page where ChemDraw put everything: skeletal formulas with their wedges, hashes and wavy bonds, a ring's double bonds drawn inside it, labels with their hydrogens, charges and isotopes, and the page's arrows, brackets, boxes and text. It works out each molecule's formula and weight, a pick on an atom names it, and Export saves the drawing as SVG, PNG or PDF, or its molecules as a MOL.
ChemDraw drawing
.cdx
Format
- MIME type
- chemical/x-cdx
- Made by
- CambridgeSoft for ChemDraw, now Revvity Signals
Inside the file
- Objects
- Tagged and nested
- Places
- Points, in 65,536ths
- Text
- Styled runs
- Written as
- Binary
Opens in every browser
Filepeek opens CDX files in Chrome, Edge, Firefox and Safari, on phones too. On their own, browsers download them.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open CDX
- WindowsChemDraw • ChemDoodle and Open Babel read it
- MacChemDraw • ChemDoodle and Open Babel read it
- iPhone and iPadNo app opens it
- AndroidNo app opens it
Questions
How do I open a CDX file without ChemDraw?
Drop it on this page or choose Peek a CDX. The drawing opens in your browser as ChemDraw laid it out, with nothing to install.
Can I get the molecule out of it?
Yes. Choose Export, then Save as MOL, which RDKit, Open Babel, MarvinSketch, Avogadro and every chemistry database read. A label like Ph or Boc goes in as the label it is, on one atom.
Why does my .cdx open as something else?
FoxPro and Visual FoxPro name their indexes .cdx too. A ChemDraw file starts with its own mark, so Filepeek tells them apart and shows what an index is.
Can I save the drawing for a paper or slides?
Yes. Choose Export, then Save the drawing as SVG, at ChemDraw's own size in points, or as PNG, sharp enough to print.