Compound record

Antimony trioxide

1309-64-4 · synergist · flame retardant

flame retardantsynergistplastics Antimony sesquioxideAntimonious oxideDiantimony trioxide

Dossier Status Obligations Why Alternatives Changes Similar Sources

CAS 1309-64-4

Formula O3Sb2

Molecular weight 291.52 g/mol

InChIKey GHPGOEFPKIHBNM-UHFFFAOYSA-N

Current EU status

Regulatory snapshot for Antimony trioxide

Antimony trioxide is currently surfaced as no current candidate list row imported in the EU.

The current imported view anchors this substance in CandidateList. The live rationale focuses on No positive Candidate List entry captured in the current imported source set, and this page is designed for fast status checks before deeper source review.

Searchers usually land here for the chemical name, CAS number, abbreviation , and the question of whether the substance is tied to SVHC, REACH, POPs, or SCIP-style compliance work.

Why this page matters

Antimony trioxide is usually searched as a formulation component rather than a stand-alone regulatory topic. Teams land here when supplier paperwork says antimony oxide, antimony sesquioxide, or CAS 1309-64-4 and the real question is whether a flame-retardant package needs deeper EU review.

In chem-data it sits in flame-retardant, synergist, and plastics routes. That makes it a portfolio-screening substance for compounds, masterbatches, and finished materials rather than a simple one-list lookup.

The main SEO opportunity is exact-name lookup plus supply-chain interpretation: antimony trioxide uses, antimony oxide CAS number, and whether the substance is part of a broader declaration or substitution exercise.

No current Candidate List row importedcurrent statuslatest imported framework state

8 Mar 2026latest anchor datelisted, effective, or checked date

Identity

CAS, formula, aliases, and use context

CAS: 1309-64-4
EC: 215-175-0
Formula: O3Sb2
Molecular weight: 291.52 g/mol
Primary class: synergist
Synonym count: 89

Search-friendly summary

Antimony trioxide , CAS 1309-64-4, is tracked here as a flame retardant substance in the synergist class.

Common names and aliases

Antimony sesquioxideAntimonious oxideDiantimony trioxideANTIMONY TRIOXIDEExiteliteTimonox

What teams usually verify first

Is antimony trioxide acting as a synergist inside a halogenated flame-retardant formulation rather than as a stand-alone additive?
Which plastic, cable, or electronics-facing product families still depend on this synergist route?
Do customer declaration workflows require a source-backed EU status check even when no positive Candidate List row is imported?

What to do next

Use the right route for status, SCIP, and source questions

Status

Current legal state, Candidate List signals, and source-backed rationale

Go here for the framework answer block, listed dates, reasons, and the imported basis for the current EU status.

Obligations

Who needs to act, what to check, and whether SCIP matters

Use this when the question is operational: SCIP, article communication, threshold review, portfolio screening, or substitute work.

Why monitored

Why this substance is monitored in the EU

Use this when you want the hazard or legal basis behind the current status, not just the status label itself.

Alternatives

Potential substitutes and nearby molecules

Use this to branch into lower-pressure neighbors, same-class analogs, and candidate-list peers.

Changes

What changed over time

Use this when you want the timeline, not just the current state.

Sources

Verify where the data came from

Use this when you need to audit provenance before trusting a claim.

Action prompts

Fast compliance and screening routes

Article duties