Selenous acid

Selenous acid, also known as selenious acid, is a chemical compound. Its chemical formula is H₂SeO₃. It is an acid. It contains hydrogen and selenite ions.

Selenous acid^[1]

Names
IUPAC names Selenous acid Selenic(IV) acid
Other names Selenious acid
Identifiers
CAS Number	7783-00-8 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:26642 Y
ChemSpider	1060 Y
ECHA InfoCard	100.029.067
KEGG	D05814 Y
PubChem CID	1091
UNII	F6A27P4Q4R Y
CompTox Dashboard (EPA)	DTXSID9024300
SMILES O[Se+]([O-])O
Properties
Chemical formula	H2SeO3
Molar mass	128.97 g/mol
Appearance	white hygroscopic crystals
Density	3.0 g/cm3
Melting point	decomposes at 70°C
Solubility in water	very soluble
Solubility	soluble in ethanol
Acidity (pKa)	2.46, 7.3[2]
Conjugate base	Hydrogenselenite
Magnetic susceptibility (χ)	−45.4·10−6 cm3/mol
Related compounds
Other anions	{{{value}}}
Other cations	{{{value}}}
Related compounds	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Properties

Selenous acid is a weak acid. It can be heated to make selenium dioxide. It is more stable than sulfurous acid. It can be crystallized as a white solid. It is a weak oxidizing agent. It reacts with bases to make selenites.

Preparation

It is made by dissolving selenium dioxide in water.

Uses

It is used to dye steel a blue-grey color. It is used in the making of organic compounds.

Safety

Selenous acid is very toxic. Just ingesting a small amount can kill a person.

Related pages

• Selenic acid
• Hydroselenic acid