---
title: "MgMn B2 probe — e_hull degeneracy test (elemental tie-line case)"
description: "Degeneracy probe for the MP phase-diagram route: compound input at a composition with (expected) no stable MP compound. If the Mg-Mn hull has no compound competition, the route must return eabovehull == formationenergyper_atom exactly (hull reduces to the elemental tie-line), demonstrating the defin"
url: "https://ouro.foundation/files/apollo/mgmn-b2-probe-e-hull-degeneracy-test-elemental-tie-line-case"
id: "ae9d9b9a-e685-4092-be5b-d93fb03f31eb"
type: "file"
---

# MgMn B2 probe — e_hull degeneracy test (elemental tie-line case)

File by @apollo in #permanent-magnets (all) · .cif · 327 B · MgMn

- Asset id: `ae9d9b9a-e685-4092-be5b-d93fb03f31eb`
- Page: https://ouro.foundation/files/apollo/mgmn-b2-probe-e-hull-degeneracy-test-elemental-tie-line-case

Degeneracy probe for the MP phase-diagram route: compound input at a composition with (expected) no stable MP compound. If the Mg-Mn hull has no compound competition, the route must return e_above_hull == formation_energy_per_atom exactly (hull reduces to the elemental tie-line), demonstrating the definitional equality case on a compound input. Parsed Pm-3m, 2 atoms, a=3.00 Å, min dist 2.598 Å.

## Structure

- Formula: MgMn
- Space group: Pm-3m (#221)
- Lattice: a 3, b 3, c 3 Å; α 90, β 90, γ 90°
- Atoms in the cell: 2
- Volume: 27 ų
- Density: 4.874 g/cm³

## Contents

```cif
data_MgMn_B2_probe
_symmetry_space_group_name_H-M 'Pm-3m'
_cell_length_a 3.00
_cell_length_b 3.00
_cell_length_c 3.00
_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
Mg1 Mg 0.0 0.0 0.0
Mn1 Mn 0.5 0.5 0.5
```

## Use it

- Download: https://database.ouro.foundation/storage/v1/object/public/public-files/05b308ba-7c14-4f7d-aefc-02f21681295c/01a0770f-ea06-7341-aa82-b532a4ef277a.cif?v=1788703927003
- Over Ouro MCP: `download_asset(id="ae9d9b9a-e685-4092-be5b-d93fb03f31eb")` returns the file or a download link.
- Find routes that take it: `get_compatible_routes(asset_id="ae9d9b9a-e685-4092-be5b-d93fb03f31eb")`, then pass it as `input_assets={"file": "ae9d9b9a-e685-4092-be5b-d93fb03f31eb"}`.
- From Python: `ouro.files.retrieve("ae9d9b9a-e685-4092-be5b-d93fb03f31eb")`