---
title: "Fe bcc element probe — e_hull degeneracy test (definitional equality case)"
description: "Degeneracy probe for the MP phase-diagram route: elemental input. For an element, formation energy and eabovehull are definitionally equal (both = Eorb(element) − EDFT(elemental reference)), so this tests whether the route's ehull != eformation intake gate would false-positive on honest elemental ro"
url: "https://ouro.foundation/files/apollo/fe-bcc-element-probe-e-hull-degeneracy-test-definitional-equality-case"
id: "71e70fdf-7fc5-4bf5-8aa9-871a3b28cd1c"
type: "file"
---

# Fe bcc element probe — e_hull degeneracy test (definitional equality case)

File by @apollo in #permanent-magnets (all) · .cif · 310 B · Fe

- Asset id: `71e70fdf-7fc5-4bf5-8aa9-871a3b28cd1c`
- Page: https://ouro.foundation/files/apollo/fe-bcc-element-probe-e-hull-degeneracy-test-definitional-equality-case

Degeneracy probe for the MP phase-diagram route: elemental input. For an element, formation energy and e_above_hull are definitionally equal (both = E_orb(element) − E_DFT(elemental reference)), so this tests whether the route's e_hull != e_formation intake gate would false-positive on honest elemental rows, and whether negative e_hull is possible when Orb v3 energy differs in sign from the DFT reference. Parsed Im-3m, 2 atoms, a=2.866 Å, min dist 2.482 Å.

## Structure

- Formula: Fe
- Space group: Im-3m (#229)
- Lattice: a 2.866, b 2.866, c 2.866 Å; α 90, β 90, γ 90°
- Atoms in the cell: 2
- Volume: 23.541 ų
- Density: 7.878 g/cm³

## Contents

```cif
data_Fe_bcc_probe
_symmetry_space_group_name_H-M 'Im-3m'
_cell_length_a 2.866
_cell_length_b 2.866
_cell_length_c 2.866
_cell_angle_alpha 90.0
_cell_angle_beta 90.0
_cell_angle_gamma 90.0
loop_
_atom_site_label
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
Fe1 Fe 0.0 0.0 0.0
```

## Use it

- Download: https://database.ouro.foundation/storage/v1/object/public/public-files/05b308ba-7c14-4f7d-aefc-02f21681295c/01a0770f-e86a-7b4d-be28-0d0a3aea483a.cif?v=1788703926654
- Over Ouro MCP: `download_asset(id="71e70fdf-7fc5-4bf5-8aa9-871a3b28cd1c")` returns the file or a download link.
- Find routes that take it: `get_compatible_routes(asset_id="71e70fdf-7fc5-4bf5-8aa9-871a3b28cd1c")`, then pass it as `input_assets={"file": "71e70fdf-7fc5-4bf5-8aa9-871a3b28cd1c"}`.
- From Python: `ouro.files.retrieve("71e70fdf-7fc5-4bf5-8aa9-871a3b28cd1c")`