Explore chemistry.
See how reactions work.
Look a molecule up in 2D and 3D. Read reactions somebody actually ran, with the conditions they used, and follow the mechanism step by step on the real structures. Prediction — asking what a set of reactants would give — is coming soon.
How it works
01
Explore
Resolve a name, formula, SMILES or InChI to one record. Rotate it in 3D, inspect any atom or bond, and read properties that each say where they came from.
Browse molecules02
Predict — coming soon
Put reactants and reagents in a flask and get candidate outcomes, ordered by whether the chemistry is compatible first and by how much precedent it has second.
03
Understand
Open a reaction in the Reaction Lab: which bonds broke and formed, the experiments behind it, and the mechanism drawn on the real structures where one is supported.
Open the Reaction Lab
Every answer says what kind of answer it is
A measured yield and a model's proposal are not the same kind of statement, and a tool that prints them in the same typeface is hiding the only thing that matters about them. ReactionLens labels every value, on every page, with where it came from.
Verified
Somebody ran it and published it. The record carries its conditions, the yield where one was reported, and a link to the source.
Verified analogue
Not this exact reaction, but documented reactions doing the same transformation on similar substrates — shown as the evidence behind a proposal, with how many records and how close they are.
Rule-derived
Worked out deterministically from chemistry that is written down and tested — a mechanism's arrows, a functional group, a calculated property. Reproducible, and not a measurement.
Predicted
A candidate from the outcome model, ranked by precedent. It is a proposal to check, never a promise, and it is capped below the top confidence while no experiment backs it.
Unknown
Said out loud rather than left blank. A field with no source reads as a zero if it is empty and as a fact if it is guessed; it is neither.
Validated, and published either way
Prediction is measured against reactions the engine has never been tuned on, and against audits that ask whether an answer is wrong rather than merely missing. Those audits pass completely; the headline ranking figure is 56.5%, which is lower than the number a competitor would quote and is the one we can defend.
Who it is for
Students
See a mechanism run on the structure in your problem set rather than on a diagram with R groups, and check your arithmetic against a calculator that shows its working.
Start with mechanismsEducators
Every page is a stable public URL you can set as reading, with no account needed and the provenance of each statement on the page.
Browse the conceptsWorking chemists
See each transformation with what it needs present and the conditions it is usually run under, backed by documented precedent. Prediction, which proposes outcomes from that precedent, is coming soon.
See the transformationsResearchers
Documented reactions searchable by structure, with the bonds each one breaks and forms and the conditions each was run under.
Search the reactionsOpen without an account
Molecules A–Z
Named structures with their identifiers, calculated and measured properties, 2D and 3D depictions, and the reactions each appears in.
Reaction records
Documented experiments filed by the chemistry they do, with conditions, yields where published, and a source for each.
Reaction mechanisms
Twenty-six classes with a canonical arrow-pushing pathway that runs on real structures. Every one states what it assumes.
Transformations
The reactions the engine can perform, each with what it needs present and the conditions it is usually run under.
The periodic table
All 118 elements with their weights, radii and configurations — and the molecules here that contain each one.
Chemistry calculators
Molar mass, molarity, dilution, limiting reagent, yield, Beer–Lambert, pH and buffers. Each shows its formula and its assumptions.
Accounts are coming soon
The public beta is free, and everything above is open now without signing up. Accounts open after the beta, bringing prediction, design, calculations and somewhere to save your work; the plans page says what each plan will allow.