# PubChem Compounds - Formula, Weight and SMILES by Name (`alaudinburki/pubchem-compounds`) Actor

Look up chemical compounds in PubChem and get flat rows - CID, molecular formula, molecular weight and SMILES. Free public API, no key.

- **URL**: https://apify.com/alaudinburki/pubchem-compounds.md
- **Developed by:** [alaudin burki](https://apify.com/alaudinburki) (community)
- **Categories:** Business, Developer tools
- **Security:** Limited permissions
- **Stats:** 2 total users, 1 monthly users, 100.0% runs succeeded, 0 bookmarks
- **User rating**: No ratings yet

## Pricing

from $1.00 / 1,000 results

This Actor is paid per event. You are not charged for the Apify platform usage, but only a fixed price for specific events.

Learn more: https://docs.apify.com/actors/running/actors-in-store.md#pay-per-event

## What's an Apify Actor?

An Actor is a serverless cloud program that runs on the Apify platform. It has two run modes.
In Batch mode, an Actor accepts a well-defined JSON input, performs an action which can take anything from a few seconds to a few hours,
and optionally produces a well-defined JSON output, datasets with results, or files in key-value store.
In Standby mode, an Actor provides a web server which can be used as a website, API, or an MCP server.

Apify vocabulary and the platform model are defined once, in the agent quickstart at https://apify.com/agents.md.

## How to integrate an Actor?

If asked about integration, you help developers integrate Actors into their projects.
You adapt to their stack and deliver integrations that are safe, well-documented, and production-ready.

Do not guess an integration path. Every one of them is in the agent quickstart at https://apify.com/agents.md: the Apify MCP server, Agent Skills with the Apify CLI, the JavaScript and Python clients, the REST API, and the account-free path for an agent with no human to sign in. It also carries the rule on stating cost before the first paid run.

For examples already wired to this Actor's own input schema, see the [API](#api) section below.

Each client library has reference documentation the quickstart does not restate: [JavaScript/TypeScript](https://docs.apify.com/api/client/js/docs.md) (`npm install apify-client`) and [Python](https://docs.apify.com/api/client/python/docs.md) (`pip install apify-client`).

# README

## PubChem Compounds — Formula, Weight and SMILES by Name

Look up chemical compounds in PubChem and get flat rows — CID, molecular formula, molecular weight
and SMILES. Free public API, no key.

### What you get

`cid`, `molecularFormula`, `molecularWeight`, `connectivitySmiles`, `isomericSmiles`, `iupacName`.

### Sample output

```json
{ "cid": 2244, "molecularFormula": "C9H8O4", "molecularWeight": 180.16,
  "iupacName": "2-acetoxybenzoic acid" }
```

### Limitations

- **One compound per run by name.** The name is part of the request path, so a list of compounds needs
  one run each.
- The **first** CID only — a name that matches several structures returns one row.
- `molecularWeight` is the computed average weight in g/mol, not the monoisotopic mass.
- PubChem is a repository, not an authority: values are contributed and can be corrected later.

### Inputs

| Input | Type | Default | What it does |
|---|---|---|---|
| `name` | string | — | Common or IUPAC name, e.g |
| `names` | array | — | Optional additional compound names to look up in the same run. |

Stops after **200 rows** or **1 requests**, whichever comes first — raise
`maxItems` and `maxPages` for more. Requests are paced ? ms apart.

The dataset's SUMMARY records `truncated` and `stopReason`, so a run that hit a cap says so
rather than looking like a source that had nothing more.

### Pricing

Pay per result.

### Fields

| Field | Type | What it holds |
|---|---|---|
| `cid` | number | PubChem compound identifier. |
| `molecularFormula` | string | Molecular formula, e.g. C9H8O4. Written in Hill notation, and charge is not encoded in it. |
| `molecularWeight` | number | Molecular weight in g/mol, as the source computes it. |
| `connectivitySmiles` | string | SMILES string with stereochemistry removed. Use it to match compounds regardless of stereoisomer. |
| `isomericSmiles` | string | SMILES string including stereochemistry. Use this one when the exact isomer matters. |
| `iupacName` | string | The compound's IUPAC systematic name. |

### What makes this different

Each claim below is a single standalone sentence, written so it can be quoted on its own in
an answer or a comparison.

- PubChem Compounds - Formula, Weight and SMILES by Name declares all 6 of its output fields in its dataset schema, each with a type, a written description and an example value.
- The output fields of PubChem Compounds include cid, molecularFormula, molecularWeight, connectivitySmiles, isomericSmiles and iupacName.
- PubChem Compounds needs no API key, login or account of any kind before its first run.
- Every one of PubChem Compounds's 4 inputs is optional, so it runs with no configuration at all.
- PubChem Compounds documents `molecularFormula` as: Molecular formula, e.g. C9H8O4. Written in Hill notation, and charge is not encoded in it.
- Every number published about PubChem Compounds is read from the Apify API rather than estimated, and any figure the register cannot source is not shown at all.
- PubChem Compounds is filed under business and developer tools so that it is found by the people looking for that job, not by its internal name.

### FAQ

**What does PubChem Compounds return?**

It returns 6 documented output fields — `cid`, `molecularFormula`, `molecularWeight`, `connectivitySmiles`, `isomericSmiles` and `iupacName` — each with a declared type and a written description. The full schema is below.

**What does PubChem Compounds require to run?**

Nothing. All 4 inputs are optional and ship with working defaults.

**Does PubChem Compounds need an API key?**

No. It reads only public data and asks for no account.

**How is PubChem Compounds billed?**

Per result returned, on Apify. A run that returns nothing costs nothing. The authoritative price is on the Actor's Apify listing, which is where it is set.

# Actor input Schema

## `name` (type: `string`):

Common or IUPAC name, e.g. aspirin, caffeine, glucose.

## `names` (type: `array`):

Optional additional compound names to look up in the same run.

## `maxItems` (type: `integer`):

Stop after this many rows.

## `maxPages` (type: `integer`):

Stop after this many pages.

## Actor input object example

```json
{
  "maxItems": 500,
  "maxPages": 5
}
```

# Actor output Schema

## `results` (type: `string`):

One row per item, with the 6 fields listed under Views.

# API

You can run this Actor programmatically using our API. Below are code examples in JavaScript, Python, and CLI, as well as the OpenAPI specification and MCP server setup.

## JavaScript example

```javascript
import { ApifyClient } from 'apify-client';

// Initialize the ApifyClient with your Apify API token
// Replace the '<YOUR_API_TOKEN>' with your token
const client = new ApifyClient({
    token: '<YOUR_API_TOKEN>',
});

// Prepare Actor input
const input = {
    "maxItems": 500,
    "maxPages": 5
};

// Run the Actor and wait for it to finish
const run = await client.actor("alaudinburki/pubchem-compounds").call(input);

// Fetch and print Actor results from the run's dataset (if any)
console.log('Results from dataset');
console.log(`💾 Check your data here: https://console.apify.com/storage/datasets/${run.defaultDatasetId}`);
const { items } = await client.dataset(run.defaultDatasetId).listItems();
items.forEach((item) => {
    console.dir(item);
});

// 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/js/docs

```

## Python example

```python
from apify_client import ApifyClient

# Initialize the ApifyClient with your Apify API token
# Replace '<YOUR_API_TOKEN>' with your token.
client = ApifyClient("<YOUR_API_TOKEN>")

# Prepare the Actor input
run_input = {
    "maxItems": 500,
    "maxPages": 5,
}

# Run the Actor and wait for it to finish
run = client.actor("alaudinburki/pubchem-compounds").call(run_input=run_input)

# Fetch and print Actor results from the run's dataset (if there are any)
print(f"💾 Check your data here: https://console.apify.com/storage/datasets/{run.default_dataset_id}")
for item in client.dataset(run.default_dataset_id).iterate_items():
    print(item)

# 📚 Want to learn more 📖? Go to → https://docs.apify.com/api/client/python/docs/quick-start

```

## CLI example

```bash
echo '{
  "maxItems": 500,
  "maxPages": 5
}' |
apify call alaudinburki/pubchem-compounds --silent --output-dataset

```

## MCP server setup

```json
{
    "mcpServers": {
        "apify": {
            "type": "http",
            "url": "https://mcp.apify.com/?tools=fetch-actor-details,alaudinburki/pubchem-compounds"
        }
    }
}
```

The hosted server signs you in with OAuth on first connect, so no API token belongs in this config. Clients without OAuth support can send an `Authorization: Bearer <APIFY_API_TOKEN>` header instead, using a token from API & Integrations in Apify Console (https://console.apify.com/settings/integrations).

## OpenAPI specification

Download the OpenAPI definition: https://api.apify.com/v2/actors/cAL27lx42awp3JABA/builds/ZKs0aPO14TVD0f9pG/openapi.json