> This page is for Developer Documentation.

> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.benchling.com/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.benchling.com/_mcp/server.

# Create Solvent

POST https://{tenant_name}.benchling.com/api/v3/solvent
Content-Type: application/json

Create a solvent in the tenant's solvent library.

Salts and solvents require the salt/solvent forms feature to be enabled on your tenant; contact your Benchling representative to turn it on. Creating a solvent requires tenant admin permissions. The solvent structure is immutable after creation. The combined salt and solvent library is limited to 2000 non-archived items, and each structure is limited to 50 atoms. An optional `code` must be unique (case-insensitive) across all salts and solvents in the tenant. Within the solvent library, names must be unique (case-insensitive) and each structure may appear only once; a salt may reuse a solvent's name or structure. Archived solvents still reserve their name and structure, so an archived match must be unarchived rather than recreated.

Reference: https://docs.benchling.com/docs/api/benchling-api/solvent/create

## Authentication

- `Authorization` header (bearer token, required) — Bearer authentication of the form `Bearer <token>`, where token is your auth token.

## Request

### Headers

- `EARLY-ACCESS` (string, optional) — Set to true to access beta operations via /api/v3.

### Body (application/json)

This endpoint expects a CreateSolventInput.

- `name` (string, required) — The name of the solvent. Must be unique (case-insensitive) within the solvent library.
- `smiles` (string, required) — The SMILES of the solvent's neutral form. The canonical SMILES and molecular formula are derived from it. Immutable after creation.
- `code` (string, optional, nullable) — Optional configurable identifier for this solvent (e.g., "H2O"). Must be unique (case-insensitive) across all salts and solvents in the tenant.

## Response

### 201

Created

- `__typename` (string, optional)
- `archiveReason` (string, optional, nullable)
- `archived` (boolean, optional)
- `calculatedMolecularWeight` (double, optional, nullable) — The molecular weight of the solvent.
- `canonicalSmiles` (string, optional) — The SMILES representation of the solvent after standardization.
- `code` (string, optional, nullable) — Optional company-specific identifier for this solvent (e.g., "MH", "DH"). Unique across both salts and solvents within a tenant.
- `createdAt` (string, optional)
- `id` (string, optional)
- `modifiedAt` (string, optional)
- `molecularFormula` (string, optional) — The molecular formula (e.g., "H2O").
- `molfile` (string, optional) — The molfile representation of the solvent.
- `name` (string, optional)

## Errors

### 400 Solvent Create Request Bad Request Error

Bad Request

- `detail` (GeneralErrorDetail, required, nullable)
- `instance` (string, required)
- `status` (integer, required)
- `title` (string, required, nullable)
- `type` (string, required)
- `invalidId` (string, optional)

### 403 Solvent Create Request Forbidden Error

Forbidden

- `detail` (GeneralErrorDetail, required, nullable)
- `instance` (string, required)
- `status` (integer, required)
- `title` (string, required, nullable)
- `type` (string, required)
- `invalidId` (string, optional)

### 404 Solvent Create Request Not Found Error

Not Found

- `detail` (GeneralErrorDetail, required, nullable)
- `instance` (string, required)
- `status` (integer, required)
- `title` (string, required, nullable)
- `type` (string, required)
- `invalidId` (string, optional)

### 409 Solvent Create Request Conflict Error

Conflict

- `detail` (GeneralErrorDetail, required, nullable)
- `instance` (string, required)
- `status` (integer, required)
- `title` (string, required, nullable)
- `type` (string, required)
- `invalidId` (string, optional)

### 429 Solvent Create Request Too Many Requests Error

Too Many Requests

- `detail` (TooManyRequestsErrorBodyDetail, required, nullable)
- `instance` (string, required)
- `status` (integer, required)
- `title` (string, required, nullable)
- `type` (string, required)
- `invalidId` (string, optional)
- `violated-policies` (list of enum, optional) — The budget policies that rejected the request, in canonical order: `user`, `integration`, then `tenant`.
  - Allowed values: `user`, `integration`, `tenant`

### 500 Solvent Create Request Internal Server Error

Internal Server Error

- `detail` (InternalServerErrorBodyDetail, required, nullable)
- `instance` (string, required)
- `status` (integer, required)
- `title` (string, required, nullable)
- `type` (string, required)
- `errorId` (string, optional)

## Types

### GeneralErrorDetail

### TooManyRequestsErrorBodyDetail

### InternalServerErrorBodyDetail

## Examples

**Request**

```json
{
  "name": "Water",
  "smiles": "O",
  "code": "H2O"
}
```

**Response**

```json
{
  "__typename": "__typename",
  "archiveReason": "archiveReason",
  "archived": true,
  "calculatedMolecularWeight": 1.1,
  "canonicalSmiles": "canonicalSmiles",
  "code": "code",
  "createdAt": "createdAt",
  "id": "id",
  "modifiedAt": "modifiedAt",
  "molecularFormula": "molecularFormula",
  "molfile": "molfile",
  "name": "name"
}
```

**SDK Code**

```python
import requests

url = "https://{tenant_name}.benchling.com/api/v3/solvent"

payload = {
    "name": "Water",
    "smiles": "O",
    "code": "H2O"
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.json())
```

```javascript
const url = 'https://{tenant_name}.benchling.com/api/v3/solvent';
const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: '{"name":"Water","smiles":"O","code":"H2O"}'
};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}
```