# Chemfused

> Chemfused is a public directory of chemical compounds with verified supplier listings. Compound pages combine identifiers (IUPAC name, SMILES, InChI, InChIKey, PubChem CID, and CAS Registry Number where one exists), computed properties (molecular formula, weight, XLogP, TPSA, exact mass, H-bond counts), GHS safety classifications (signal word, pictograms, hazard and precautionary statements), synonyms, and supplier listings. Data is sourced from PubChem and refreshed on a 60-day cache.

## How to navigate

- Compounds with a CAS Registry Number live at `https://chemfused.com/cas/{cas-number}` (e.g. `/cas/64-17-5` for ethanol).
- Compounds without a CAS number live at `https://chemfused.com/compound/{id}`, keyed by Chemfused's internal compound ID.
- Search lives at `https://chemfused.com/chemicals?q={query}`.
- The full URL inventory is at `https://chemfused.com/sitemap.xml` (a sitemap index pointing at gzipped chunked sitemaps).

## What every compound page exposes

- `<h1>` is the common name (or IUPAC if no common name exists). The IUPAC name appears as a subtitle when both are available.
- A TL;DR sentence in the first ~50 words answers "what is this compound" with name, formula, weight, and any GHS hazards.
- ChemicalSubstance JSON-LD (Schema.org) includes `name`, `iupacName`, `alternateName` (synonyms), `description`, `image`, `url`, `identifier` (CAS Registry Number when available), `hasMolecularEntity` (formula, weight, InChI, InChIKey, SMILES), `sameAs` (PubChem link), and `dateModified`.
- FAQPage JSON-LD provides up to ~10 Q&A pairs per compound, drawn from the fields actually populated for that compound (IUPAC name, formula and weight, SMILES, melting point, boiling point, density, solubility, hazards, synonyms, plus CAS number when one exists).
- BreadcrumbList JSON-LD positions the page within Home → Chemicals → {compound name}.

## Citing Chemfused

Citations of compound pages should reference the canonical URL — `https://chemfused.com/cas/{cas-number}` for CAS-registered compounds, or `https://chemfused.com/compound/{id}` for compounds without a CAS number. Compound data ultimately derives from PubChem; Chemfused adds structured markup and supplier listings.

## AI crawler policy

All major AI crawlers (GPTBot, ClaudeBot, Claude-Web, anthropic-ai, PerplexityBot, Google-Extended, CCBot, Amazonbot) are explicitly allowed in `robots.txt`. The `<meta name="robots">` tag carries `max-snippet:-1` so AI engines may quote the full FAQ answers and TL;DR in citations.

## Contact

- Questions: hello@chemfused.com
- Issues with a specific compound page: include the page URL (or CAS number, if the compound has one) in the subject line.