---
id: "smiles"
kind: "datatype"
status: "draft"
is_pii: false
categories: ["chemistry", "science"]
langs: ["common"]
quality: 75
url: "http://registry.apicrafter.io/datatype/smiles"
---

# SMILES chemical notation (`smiles`)

> **Draft.** Draft records have not been reviewed yet and may be incomplete or wrong; do not treat them as authoritative for legal or compliance decisions.

Simplified Molecular-Input Line-Entry System (SMILES): a line notation that writes the structure of a molecule as a short ASCII string. Atoms are written by their element symbols, double and triple bonds by = and #, branches in parentheses and ring closures by digits; lowercase letters mark aromatic atoms. One molecule has many valid SMILES strings. Canonical SMILES picks one of them, and isomeric SMILES also records stereochemistry and isotopes. PubChem and Wikidata publish both forms. The record has no regexp: the SMILES character set also matches ordinary words, so a chemistry parser such as RDKit or Open Babel is needed to check a value.

- Personal data (PII): no
- Categories: Chemistry (chemistry), Scientific (science)
- Countries: global
- Languages: Common to most languages (common)
- Classification: identifier

## Examples

- `CCO` — Ethanol
- `C1=CC=CC=C1` — Benzene, Kekulé form
- `c1ccccc1` — Benzene, aromatic form
- `O=C=O` — Carbon dioxide
- `CC(=O)OC1=CC=CC=C1C(=O)O` — Aspirin
- `[Au]` — Gold
- `O=C(O)[C@@H](N)C` — L-alanine, isomeric SMILES

## Mappings

- autotype: `smile`
- bioregistry: `smiles`
- schema_org: `smiles`

## Supported by tools

- `autotype`

## Translations

- ru: Нотация SMILES: Строковая запись структуры молекулы (Simplified Molecular-Input Line-Entry System): атомы, связи, ветви и циклы записываются ASCII-символами.

## Sources

- wikipedia: <https://en.wikipedia.org/wiki/Simplified_Molecular_Input_Line_Entry_System>
- wikidata: <https://www.wikidata.org/wiki/Property:P233>
- wikidata: <https://www.wikidata.org/wiki/Property:P2017>
- schema.org: <https://schema.org/smiles>
- doc: <http://opensmiles.org/opensmiles.html>
- other: <https://github.com/congy/AutoType/blob/master/data_release/smile.txt>

## Quality

Score 75/100. Missing: regexp, negative example.

JSON: <http://registry.apicrafter.io/api/v1/datatypes/smiles.json> · Edit: <https://github.com/apicrafter/metacrafter-registry/edit/main/data/datatypes/any/chemistry/smiles.yaml>