Step 1 — normalize the drawingStep 2 of 17 of the InChI walkthrough. Before anything is numbered, the drawing is reduced to a single-bond skeleton plus hydrogen counts. This normalization is why the two usual nitro-group drawings, the Kekulé and aromatic forms of benzene, and every way of writing a zwitterion all give one identifier. Try redrawing this nitromethane with a pentavalent nitrogen and no charges — the InChI does not move.It opens on C[N+](=O)[O-], drawn live, so the layer under discussion changes as you change the structure.Convert a structure to its InChI and InChIKey and back, convert a whole CSV, XLSX or SDF file, learn how the identifier is derived, and practise writing its layers. The InChI engine is WebAssembly running in your browser, so the tool needs JavaScript — and nothing you open ever leaves your machine.

Convert — a structure in, an InChI out

Batch — a whole CSV, XLSX or SDF file

Tutorial — how an InChI is derived

Exercises — write the layers yourself

Cheatsheet — every layer in a table

Tests — the IUPAC regression corpora

Download — take the engine away

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