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CAS 1 record

CAS 51274-00-1

CAS 51274-00-1 matches 1 EU annex record across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 51274-00-1
CAS 51274-00-1PubChem CID 23320441

C.I. Pigment Yellow 42

IUPAC name
iron(3+);oxygen(2-);hydroxide;hydrate
Molecular formula
FeH3O3
Molecular weight
106.87 g/mol
Exact mass
106.943154 Da
Topological polar surface area
3.0 Ų
Hydrogen-bond donors
2
Hydrogen-bond acceptors
3
Covalent units
4
Defined stereocentres
0

Also known as

Ferric oxide YellowEX438O2MRTC.I. 77492RefChem:1080569Yellow iron oxideFerric oxide, yellowBayferrox 920UNII-EX438O2MRT
16 more reported names
Iron hydroxide oxide yellowFerric oxide, yellow [NF]CCRIS 4378EINECS 257-098-5MAPICO YELLOWIRON OXIDE,YELLOWFERRIC OXIDE,YELLOWEC 257-098-5HYDRATED FERRIC-OXIDEFERRIC OXIDE, HYDRATEDINS NO.172(III)INS-172(III)FERRIC OXIDE YELLOW [II]FERRIC OXYHYDROXIDE HYDRATEHYDRATED IRON (III) OXIDEIRON OXIDE,YELLOW [VANDF]
Open full PubChem recordPubChem annotations3D structure image

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 51274-00-1

1 total
Annex
IV
Entry
136

CI 77492

Iron Oxide Yellow

Purity criteria as set out in Commission Directive 95/45/EC (E172)

EC
257-098-5

How CAS 51274-00-1 is used on this site

CAS 51274-00-1 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 1 EU annex record shares this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 51274-00-1 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 51274-00-1 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

The INCI Checker accepts ingredient names, CAS numbers and EC numbers. Check this CAS number directly, then verify the result against supplier specification sheets and every linked annex condition.
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