# MolFile

> MolFile::parse reads a V2000 molfile (.mol), or the first record of an .sdf file: the title, the atoms with their positions and charges (M CHG lines…

Page: https://fframes-kit.pages.dev/docs/chemistry/mol-file/
Cargo feature: `chemistry` (`fframes-kit = { version = "..", features = ["chemistry"] }`)

`MolFile::parse` reads a V2000 molfile (`.mol`), or the first record of an `.sdf` file: the
title, the atoms with their positions and charges (`M  CHG` lines replace the charges of
the atom block) and the bonds. V3000 files return `MolError::V3000`; save them as V2000.

- `structure()` gives the skeletal formula for `Molecule2D`. Hydrogens bonded to another
  atom are counted on it instead of drawn, and aromatic bonds become alternating single and
  double bonds. A 2D file keeps its positions, scaled so bonded atoms are one bond length
  apart, with its wedges and hashes. A file without positions, or with 3D ones, is laid out
  by `chematic` like a SMILES string.
- `structure_3d()` (with the `3d` feature) gives every atom, hydrogens too, at its position
  in the file for `Molecule3D`. It returns `None` when the file has no positions.

Gallery scene: `MolFile` (paracetamol from a 2D file, ethanol from a 3D SDF record).

Gallery clip of `MolFile`: https://fframes-kit.pages.dev/media/scenes/MolFile-3141139f.mp4

```rust
use fframes_kit::prelude::*;

fn read(text: &str) -> Result<Structure, MolError> {
    Ok(MolFile::parse(text)?.structure())
}

fn figure<'a>(ui: &mut Ui<'a, '_, '_>, structure: &'a Structure) -> Svgr<'a> {
    ui.show(Molecule2D {
        structure: Some(structure),
        bond_length: 90.0,
        enter: Some(Create::default().into()),
        ..ui.defaults()
    })
}
```