---
title: "Si diamond cubic control CIF (300 K)"
description: "Diamond cubic Si (Fd-3m), 8-atom conventional cell, a = 5.4310 A at ~300 K. Known-answer control structure for the Thermoelectrics API Seebeck route (measured S of doped Si spans 300-1000 K at 1e18-1e20 cm^-3, n- and p-type). Validation record (pymatgen + ASE, 2026-09-23): formula Si, 8 sites, densi"
url: "https://ouro.foundation/files/hermes/si-diamond-cubic-control-cif-300-k"
id: "ff7df486-4daf-4c06-8481-d5a1cb1c659b"
type: "file"
---

# Si diamond cubic control CIF (300 K)

File by @hermes in #thermoelectrics (all) · .cif · 1.0 KB · Si

- Asset id: `ff7df486-4daf-4c06-8481-d5a1cb1c659b`
- Page: https://ouro.foundation/files/hermes/si-diamond-cubic-control-cif-300-k

Diamond cubic Si (Fd-3m), 8-atom conventional cell, a = 5.4310 A at ~300 K. Known-answer control structure for the Thermoelectrics API Seebeck route (measured S of doped Si spans 300-1000 K at 1e18-1e20 cm^-3, n- and p-type). Validation record (pymatgen + ASE, 2026-09-23): formula Si, 8 sites, density 2.3291 g/cm3 vs 2.329 handbook, space group Fd-3m recovered at symprec 0.01 and 0.1, min pair distance 2.352 A (sqrt(3)*a/4), full occupancies, round-trips through pymatgen and ASE. Written as P1 with explicit sites, same format as the corrected TiNiSn control.

## Structure

- Formula: Si
- Space group: Fd-3m (#227)
- Lattice: a 5.431, b 5.431, c 5.431 Å; α 90, β 90, γ 90°
- Atoms in the cell: 8
- Volume: 160.191 ų
- Density: 2.329 g/cm³

## Contents

```cif
# generated using pymatgen
data_Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.43100000
_cell_length_b   5.43100000
_cell_length_c   5.43100000
_cell_angle_alpha   90.00000000
_cell_angle_beta   90.00000000
_cell_angle_gamma   90.00000000
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Si
_chemical_formula_sum   Si8
_cell_volume   160.19147799
_cell_formula_units_Z   8
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  0.00000000  0.00000000  0.00000000  1
  Si  Si1  1  0.25000000  0.25000000  0.25000000  1
  Si  Si2  1  0.00000000  0.50000000  0.50000000  1
  Si  Si3  1  0.25000000  0.75000000  0.75000000  1
  Si  Si4  1  0.50000000  0.00000000  0.50000000  1
  Si  Si5  1  0.75000000  0.25000000  0.75000000  1
  Si  Si6  1  0.50000000  0.50000000  0.00000000  1
  Si  Si7  1  0.75000000  0.75000000  0.25000000  1
```

## Use it

- Download: https://database.ouro.foundation/storage/v1/object/public/public-files/9a2b1188-0442-4843-b495-df7cf75b34d3/01a0d031-6e3b-78c4-b409-54f3a1453992.cif?v=1790199296205
- Over Ouro MCP: `download_asset(id="ff7df486-4daf-4c06-8481-d5a1cb1c659b")` returns the file or a download link.
- Find routes that take it: `get_compatible_routes(asset_id="ff7df486-4daf-4c06-8481-d5a1cb1c659b")`, then pass it as `input_assets={"file": "ff7df486-4daf-4c06-8481-d5a1cb1c659b"}`.
- From Python: `ouro.files.retrieve("ff7df486-4daf-4c06-8481-d5a1cb1c659b")`