Look up a chemical compound
Exactchemistry_compound_lookupDeterministic and authoritative — the canonical answer for this input.
Look up a chemical compound's canonical properties from PubChem by any common identifier (name, CAS, CID, SMILES, InChI, InChIKey). Returns formula, molecular weight, IUPAC name, canonical/isomeric SMILES, InChI, InChIKey, and the PubChem CID. Unknown compound -> confidence 0.0; PubChem outage/throttle -> retryable error. For the full synonym list use chemistry_synonyms; batch via chemistry_compound_lookup_batch. Charges 2 cost_units; 1 when the query is empty (rejected locally before PubChem is called); an unknown query_type is a request-shape error, rejected unbilled (INVALID_INPUT).
Parameters
querystringrequiredThe compound identifier to look up (e.g. 'aspirin').
query_typestringoptionalIdentifier type: name, cas, cid, smiles, inchi, or inchikey. A CAS number resolves as a PubChem name synonym. Default 'name'.
Call it
curl -X POST https://api.snipget.ai/v1/chemistry/compound/lookup \
-H "Authorization: Bearer sk_live_..." \
-H "Content-Type: application/json" \
-d '{"query":"aspirin"}'The Batch tab sends up to 1000 inputs in one call via /v1/chemistry/compound/lookup/batch.
FAQ
Why use this instead of asking a model for the formula?
Models hallucinate structures, SMILES, and molecular weights. This resolves a compound against PubChem and returns the real formula, molecular weight, IUPAC name, canonical and isomeric SMILES, InChI, InChIKey, and CID, all from maintained data you should not guess.
What can I look it up by?
Set query_type to name, cas, cid, smiles, inchi, or inchikey. A CAS number resolves through PubChem's name synonyms, so you can paste in whatever identifier you have.
Is the result authoritative?
Yes. It is a deterministic lookup against PubChem, so the same query returns the same canonical record. It does not approximate.
How is this different from synonyms?
This returns one compound's canonical properties (formula, weight, identifiers). Use chemistry_synonyms when you want the full list of alternate names for that compound.
What if the compound is unknown or PubChem is down?
An unknown compound returns confidence 0, not an error. A real PubChem outage returns a 503, so a missing compound and a service problem are never confused.