chem-name-resolver

A pure-Rust library for resolving IUPAC chemical names to SMILES strings and molecular graphs. The Rust equivalent of Java's OPSIN, with WebAssembly support.

Why chem-name-resolver?

Converting an IUPAC name like "2,4-pentanedione" to its SMILES representation "CC(=O)CC(=O)C" sounds simple, but every existing solution comes with a significant trade-off:

△ = partial / experimental

This library fills the gap: a pure-Rust, WASM-compatible, offline IUPAC→SMILES engine with CJK support. It enables:

• Browser-side chemistry — ship a WASM module and resolve names client-side with zero server round-trips
• Rust-native tooling — integrate into CLI tools, database indexers (e.g. Cheminee), or Axum services without pulling in a JVM or C++ build
• Japanese/Chinese workflows — normalize katakana and kanji chemical names in the same pipeline, without a separate preprocessing step
• Lightweight embedding — the release profile produces a small binary (opt-level = "s", LTO enabled) suitable for edge deployments

Features

• Pure Rust — no C/C++ dependencies (no RDKit, no Boost)
• WASM-compatible — compiles to wasm32-unknown-unknown
• CJK support — resolves Japanese katakana names (メタン, エタノール, …)
• Zero-copy normalization — returns Cow::Borrowed when input needs no changes
• JSON serialization — ResolveResult implements serde::Serialize

Quick Start

use chem_name_resolver::resolve;

// Systematic IUPAC name
let r = resolve("propan-2-one").unwrap();
assert_eq!(r.smiles, "CC(=O)C");
assert_eq!(r.molecular_formula.as_deref(), Some("C3H6O"));
assert!((r.molecular_weight.unwrap() - 58.08).abs() < 0.01);

// Trivial name
let r = resolve("acetone").unwrap();
assert_eq!(r.smiles, "CC(=O)C");

// Japanese katakana
let r = resolve("メタン").unwrap();
assert_eq!(r.smiles, "C");

// n- prefix
let r = resolve("n-butane").unwrap();
assert_eq!(r.smiles, "CCCC");

// JSON output
let json = serde_json::to_string(&r).unwrap();

Coverage

Normalizer

Dictionary

IUPAC Parser

Chain stems: methane–decane (C1–C10), undecane–icosane/eicosane (C11–C20)

Suffixes:

Multiplier prefixes di-, tri-, tetra- are supported for all suffixes.

Substituents:

Multiplier prefixes di-, tri-, tetra- are supported (e.g. 2,3-dichlorobutane → CC(C(C)Cl)Cl).

Output

pub struct ResolveResult {
    pub smiles: String,
    pub canonical_name: String,
    pub source: ResolveSource,           // Dictionary | Parser
    pub molecular_formula: Option<String>, // Hill notation, e.g. "C2H6O"
    pub molecular_weight: Option<f64>,     // g/mol
}

molecular_formula and molecular_weight are None when resolved via DirectSmiles (e.g. benzene).

Installation

[dependencies]
chem-name-resolver = "0.1"

# for JSON output
serde_json = "1"

Building & Testing

# run all 75 tests
cargo test

# verify WASM build
rustup target add wasm32-unknown-unknown
cargo build --features wasm --target wasm32-unknown-unknown

# benchmarks
cargo bench

WASM Usage

import init, { resolve_to_smiles, resolve_full, normalize_name } from './chem_name_resolver.js';

await init();
console.log(resolve_to_smiles("propan-2-one")); // "CC(=O)C"
console.log(normalize_name("α-D-glucose"));     // "alpha-d-glucose"

// Full result as JSON string
const json = resolve_full("ethanol");
// '{"smiles":"CCO","canonical_name":"ethanol","source":"Dictionary","molecular_formula":"C2H6O","molecular_weight":46.069}'

CLI Usage

cargo install chem-name-resolver --features cli

chem resolve ethanol
# {
#   "smiles": "CCO",
#   "canonical_name": "ethanol",
#   "source": "Dictionary",
#   "molecular_formula": "C2H6O",
#   "molecular_weight": 46.069
# }

chem resolve --smiles "propan-2-one"
# CC(=O)C

Known Limitations

• Cyclic and aromatic compounds are not parsed (dictionary lookup only)
• Stereochemistry (R/S, E/Z) is not supported

Roadmap

• Branched alkyl substituents (isopropyl, tert-butyl, …)
• cyclo- prefix (cyclic compounds)
• CLI binary (chem resolve "ethanol")
• Chinese/kanji chemical name dictionary
• Canonical SMILES (subtree-signature DFS ordering)
• Python bindings (PyO3 / Maturin)

License

MIT OR Apache-2.0