---
license: other
pretty_name: moses_train
tags:
- chemistry
- molecules
- graph-generation
- flow-matching
size_categories:
- 1M<n<10M
---

# nico8771/moses_train — cleaned MOSES (train split)

Each row is a molecule as **canonical SMILES** plus RDKit-recomputed targets. MOSES is
neutral by construction, so molecules are featurized over **7 atom types** with **no
formal charges**, and **aromatic bonds are kept as their own class** (no kekulization)
so the model learns aromaticity directly.

> Source: official MOSES `train.csv.gz` (molecularsets/moses). Code:
> <https://github.com/Nico-Conti/flow-matching-molecules> (`dataset/`).

## Schema

| column | type | description |
|---|---|---|
| `smiles` | string | canonical, single-fragment SMILES (post-sanitize) |
| `y` | list[float] | RDKit targets, columns = `logP`, `qed`, `SAS` |

## Pipeline

1. **Parse** with RDKit; unparseable dropped.
2. **Standardize** — remove stereochemistry, sanitize (MOSES is neutral; *no* Uncharger).
3. **Featurize** over atom vocab (`C`, `N`, `S`, `O`, `F`, `Cl`, `Br`); atoms outside the vocab dropped.
4. **Round-trip check** — `smiles -> (X, E) -> mol -> smiles`, aromatic bonds preserved.

Bonds use 5 classes (none / single / double / triple / aromatic).
Targets (`logP`, `qed`, `SAS`) are recomputed from the sanitized SMILES with RDKit.

### Drop / keep counts (this build)

| outcome | count |
|---|---|
| `kept` | 1,415,728 |
| `kept_no_roundtrip` | 168,935 |

Kept: **1,584,663** molecules.