Iron(III) oxide-hydroxide

Iron(III) oxide-hydroxide
Names
	IUPAC name Iron(III) oxide-hydroxide
	Other names Metaferric acid; Ferric oxyhydroxide; Goethite
Identifiers
CAS Number	1310–14–1 ; 20344–49–4 ;
3D model (JSmol)	Interactive image;
ChemSpider	82623 ;
ECHA InfoCard	100.039.754
EC Number	215–176–6;
MeSH	Goethite
PubChem CID	91502;
UNII	87PZU03K0K ;
CompTox Dashboard (EPA)	DTXSID801318339 DTXSID3042057, DTXSID801318339 ;
	InChI InChI=1S/Fe.H2O.O/h;1H2;/q+1;;/p-1 Key: AEIXRCIKZIZYPM-UHFFFAOYSA-M ;
	SMILES O=[Fe]O;
Properties
Chemical formula	FeO(OH)
Appearance	Vivid, dark orange, opaque crystals
Odor	odorless
Density	4.25 g/cm3
Solubility in water	insoluble at pH 7
Solubility product (Ksp)	2.79×10−39 for Fe(OH)3
Hazards
NFPA 704 (fire diamond)	1 0 0
Pharmacology
ATC code	B03AB04 (WHO)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Iron(III) oxide-hydroxide or ferric oxyhydroxide is the chemical compound of iron, oxygen, and hydrogen with formula FeO(OH).

The compound is often encountered as its hydrates - FeO(OH)·nH
₂O, e.g. in rust. The monohydrate FeO(OH)·H
₂O (sometimes incorrectly labelled Fe(OH)
₃) is often referred to as iron(III) hydroxide, hydrated iron oxide, yellow iron oxide, or Pigment Yellow 42.