# /materialsproject/structures

`POST /api/materialsproject/structures`

Price: 1 credit

Get one Materials Project crystal structure by its id. Returns the unit cell — lattice vectors, Cartesian site positions, species and the species occupying each site — together with the composition, the chemical formulas and the formation energy and energy above hull per DFT functional.

## How to use it

The only endpoint that returns atomic coordinates; materialsproject/structures/search returns everything else about the same material but no geometry, so fetch here once a search has picked the id. Lengths are angstroms and energies electronvolts per atom. `thermodynamics` holds one entry per DFT functional and a missing `r2scan` entry means no r2SCAN calculation exists, not a gap in our parsing. This mirror carries no symmetry data at all, so space groups, Wyckoff positions, band gaps, density, elastic constants and magnetism are unavailable here whatever the material — see the search endpoint's hint for what the mirror does and does not cover.

## Parameters

- `access-token` (string, required)

## Request body

- `timeout` (integer) — Max scrapping execution timeout (in seconds) (default: 300; min: 20; max: 1500)
- `structure_id` (string, required) — Materials Project structure id. A bare number is read as an mp- id, and a materialsproject.org or OPTIMADE URL is accepted in place of the id (examples: "mp-149", "149", "https://next-gen.materialsproject.org/materials/mp-149"; minLength: 1)

## Response

### 200 — Successful Response

- `@type` (string) (default: "MaterialsprojectStructureDetail")
- `id` (string, required)
- `source_url` (string) (default: "")
- `immutable_id` (string) (default: "")
- `last_modified_at` (integer, nullable)
- `formula_descriptive` (string) (default: "")
- `formula_reduced` (string) (default: "")
- `formula_hill` (string) (default: "")
- `formula_anonymous` (string) (default: "")
- `chemical_system` (string) (default: "")
- `elements` (array) (default: [])
- `element_ratios` (array) (default: [])
- `element_count` (integer, nullable)
- `site_count` (integer, nullable)
- `dimension_types` (array) (default: [])
- `periodic_dimension_count` (integer, nullable)
- `structure_features` (array) (default: [])
- `thermodynamics` (array) (default: [])
  - `@type` (string) (default: "MaterialsprojectThermo")
  - `functional` (string) (default: "")
  - `thermo_id` (string) (default: "")
  - `energy_above_hull` (number, nullable)
  - `formation_energy_per_atom` (number, nullable)
  - `last_updated_at` (integer, nullable)
- `lattice_vectors` (array) (default: [])
- `cartesian_site_positions` (array) (default: [])
- `species` (array) (default: [])
  - `@type` (string) (default: "MaterialsprojectSpecies")
  - `name` (string) (default: "")
  - `chemical_symbols` (array) (default: [])
  - `concentration` (array) (default: [])
- `species_at_sites` (array) (default: [])

## Errors

### 422 — Validation Error

The request body did not validate

What to do: Check the fields against this schema. A URN with the wrong prefix is the most common cause.

- `detail` (array)
  - `loc` (array, required)
  - `msg` (string, required)
  - `type` (string, required)
  - `input` (any)
  - `ctx` (object)

### 408

The request ran past its time limit

What to do: Raise `timeout` in the request body, up to the maximum this endpoint documents. Lowering `count` or turning off the `with_*` flags also helps, because less work finishes sooner.

### 412

No structure with that id. Ids look like mp-149; an internal immutable_id or an mvc- id does not resolve

What to do: Retrying will not help: either the entity does not exist, or the input points at a different one.

### 429

Too many requests: a rate limit or a usage window is exhausted

What to do: When the response carries an X-Retry-After header, wait that many seconds and retry: the same number is in the body as `detail.retry_after`, and the limit clears once that window passes. The message in the body names the limit that was hit.

### 500

Something broke on our side

What to do: Retrying will not help. If it keeps happening, send us the X-Request-ID from the response headers.

### 529

Rate limit reached, or the endpoint is overloaded

What to do: Wait at least 30 seconds, then retry.

## Response envelope

Success: Array of objects (may be empty if no results)

Error: Error may coexist with partial results if it occurs mid-execution. Check X-Error header and status code.

Every response carries these headers:

- `X-Error` — Error message text (present only on error)
- `X-Request-ID` — Unique request identifier
- `X-Execution-Time` — Execution time in seconds
- `X-Result-Count` — How many records the body carries. 0 means an empty result, which is a normal answer and not by itself an error. A non-zero count can come back together with X-Error when the failure happened partway through — read this header and X-Error independently.
- `X-Total-Available-Results` — How many records exist for this query, when the endpoint can say. On a `dry_run` request this is the answer and the body is empty. It saturates: the endpoint's documented maximum means 'at least that many', any smaller number is exact.
- `X-Warning` — Present when the request body carried keys this endpoint does not document. They were ignored, so any filter you meant to apply through them did not apply. Check the spelling against this schema and retry.
- `X-Retry-After` — Seconds to wait before retrying. Present only on 429.