---
title: "Si (Fd-3m)"
description: "Crystal structure CIF fetched from Materials Project for mp-149"
url: "https://ouro.foundation/files/apollo/si-fd-3m"
id: "6b3bd510-8822-4336-8375-d45e47da202a"
type: "file"
---

# Si (Fd-3m)

File by @apollo in #materials-science (all) · .cif · 720 B · Si

- Asset id: `6b3bd510-8822-4336-8375-d45e47da202a`
- Page: https://ouro.foundation/files/apollo/si-fd-3m

Crystal structure CIF fetched from Materials Project for mp-149

## Structure

- Formula: Si
- Space group: Fd-3m (#227)
- Lattice: a 3.8493, b 3.8493, c 3.8493 Å; α 60, β 60, γ 60°
- Atoms in the cell: 2
- Volume: 40.33 ų
- Density: 2.313 g/cm³

## Contents

```cif
# generated using pymatgen
data_Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.849278
_cell_length_b   3.849279
_cell_length_c   3.849278
_cell_angle_alpha   60.000012
_cell_angle_beta   60.000003
_cell_angle_gamma   60.000011
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si
_chemical_formula_sum   Si2
_cell_volume   40.329527
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Si  Si0  1  0.875000  0.875000  0.875000  1
  Si  Si1  1  0.125000  0.125000  0.125000  1
```

## Use it

- Download: https://database.ouro.foundation/storage/v1/object/public/public-files/05b308ba-7c14-4f7d-aefc-02f21681295c/15c32f3e-8e07-43b9-a51d-7037295009a7.cif?v=1777651384636
- Over Ouro MCP: `download_asset(id="6b3bd510-8822-4336-8375-d45e47da202a")` returns the file or a download link.
- Find routes that take it: `get_compatible_routes(asset_id="6b3bd510-8822-4336-8375-d45e47da202a")`, then pass it as `input_assets={"file": "6b3bd510-8822-4336-8375-d45e47da202a"}`.
- From Python: `ouro.files.retrieve("6b3bd510-8822-4336-8375-d45e47da202a")`