---
name: materials-project-e78974e7900c
description: "Query the Materials Project API v3 for crystal structures, band gaps, formation energies, and thermodynamic stability of 150k+ inorganic materials. Use when: (1) searching materials by chemical formula, (2) looking up material properties by MP ID, (3) filtering materials by band gap, energy, or density, (4) finding stable phases for a composition. NOT for: organic molecules (use pubchem-compound), proteins (use uniprot-protein), drug compounds (use chembl-drug)."
metadata: { "openclaw": { "emoji": "\U0001F9F1", "requires": { "bins": ["curl"] } } }
---

# Materials Project API

Search and retrieve computed materials data from the Materials Project database
(v3 API). Covers 150k+ inorganic crystalline materials with DFT-computed properties.

## Authentication

All requests require the `X-API-KEY` header set to your Materials Project API key.
Store it in the `MP_API_KEY` environment variable.

```bash
export MP_API_KEY="your_api_key_here"
```

## API Base URL

```
https://api.materialsproject.org/v3
```

## Search by Chemical Formula

```bash
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?formula=Fe2O3&_fields=material_id,formula_pretty,band_gap,formation_energy_per_atom,energy_above_hull,symmetry,density&_limit=10"
```

## Lookup by Material ID

```bash
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?material_ids=mp-149&_fields=material_id,formula_pretty,band_gap,formation_energy_per_atom,energy_above_hull,symmetry,density,structure"
```

## Filter by Band Gap Range

```bash
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?band_gap_min=1.0&band_gap_max=2.0&_fields=material_id,formula_pretty,band_gap,formation_energy_per_atom&_limit=20"
```

## Filter by Thermodynamic Stability

Find materials on or near the convex hull (energy_above_hull close to 0 = stable):

```bash
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?energy_above_hull_max=0.025&elements=Li,Fe,O&_fields=material_id,formula_pretty,energy_above_hull,formation_energy_per_atom&_limit=20"
```

## Filter by Elements

Search for materials containing specific elements:

```bash
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?elements=Si,Ge&_fields=material_id,formula_pretty,band_gap,density&_limit=15"
```

## Key Properties

| Property                    | Description                                   | Unit       |
|-----------------------------|-----------------------------------------------|------------|
| `band_gap`                  | Electronic band gap                           | eV         |
| `formation_energy_per_atom` | Formation energy per atom from elements        | eV/atom    |
| `energy_above_hull`         | Energy above convex hull (0 = stable)          | eV/atom    |
| `symmetry`                  | Space group and crystal system                 | -          |
| `density`                   | Computed density                               | g/cm^3     |
| `volume`                    | Unit cell volume                               | Angstrom^3 |
| `nsites`                    | Number of sites in the unit cell               | -          |

## Parse Results with Python

```bash
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?formula=TiO2&_fields=material_id,formula_pretty,band_gap,energy_above_hull,density&_limit=10" \
  | python3 -c "
import sys, json
data = json.load(sys.stdin)
for mat in data.get('data', []):
    mid = mat.get('material_id', 'N/A')
    formula = mat.get('formula_pretty', 'N/A')
    bg = mat.get('band_gap', 'N/A')
    ehull = mat.get('energy_above_hull', 'N/A')
    rho = mat.get('density', 'N/A')
    print(f'{mid:12s} {formula:10s} Eg={bg} eV  Ehull={ehull} eV/at  rho={rho} g/cm3')
"
```

## Pagination

Use `_limit` and `_skip` for pagination:

```bash
# First page
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?elements=Cu,Zn&_fields=material_id,formula_pretty&_limit=50&_skip=0"

# Second page
curl -s -H "X-API-KEY: $MP_API_KEY" \
  "https://api.materialsproject.org/v3/materials/summary/?elements=Cu,Zn&_fields=material_id,formula_pretty&_limit=50&_skip=50"
```

## Common Query Patterns

- **Solar cell absorbers**: `band_gap_min=1.0&band_gap_max=1.8&energy_above_hull_max=0.05`
- **Wide band gap semiconductors**: `band_gap_min=3.0&band_gap_max=6.0`
- **Metals**: `band_gap_max=0&is_metal=true`
- **Specific composition**: `chemsys=Li-Fe-P-O` (all materials in that chemical system)

## Best Practices

1. Always specify `_fields` to limit response size and speed up queries.
2. Use `energy_above_hull_max=0.025` to filter for thermodynamically stable phases.
3. Check `is_deprecated` field to avoid outdated entries.
4. Use `chemsys` for phase diagram queries across a chemical system.
5. Rate limit: keep requests under 5 per second to avoid throttling.
6. For bulk downloads, use the mp-api Python client instead of REST calls.

## Data Integrity Rule

NEVER fabricate database results from training data. Every protein ID, gene name, compound property, pathway ID, structure detail, and metadata MUST come from an actual API response in this conversation. If the API returns no results, errors, or partial data, report exactly what happened. Do not "fill in" missing data from memory or make up identifiers.


---
Source attribution: beita6969
Original project: https://github.com/beita6969/ScienceClaw/blob/e925f732c7ca435f557e88075bc47a58f1e984f1/skills/materials-project/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2025 Peter Steinberger

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: beita6969
Original project: https://github.com/beita6969/ScienceClaw/blob/e925f732c7ca435f557e88075bc47a58f1e984f1/skills/materials-project/SKILL.md
Attribution basis: Source repository record

Fields of work: Data & Analytics, Education & Research
Roles: Data Scientist, Market Research Analyst, Researcher
Specialties: API
Tools: Materials Project Api
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 14b65f67db80552cebd0d91c29d1c272dc58ba5094045a4b1b57ab9d7caa803d