Numbering 3 — break the remaining tiesStep 6 of 17 of the InChI walkthrough. Refinement stalls when atoms are genuinely symmetric — a benzene ring, the two halves of naphthalene. Those form an equivalence class no invariant can split, so one atom is picked out of the class by hand and refinement resumes. Which one is picked is arbitrary, and that is exactly the step this guide cannot promise you will reproduce.It opens on c1ccc2ccccc2c1, 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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