Hydrogen selenide

This article is about the acidic gas. For hydrogen selenide with one hydrogen taken away, see hydroselenide.

Hydrogen selenide, also known as hydroselenic acid, selenium hydride, or selane, is a chemical compound. Its chemical formula is H₂Se. It is an acid. It contains hydrogen and selenide ions.

Hydrogen selenide

Structural diagram of the hydrogen selenide molecule Space-filling model of the hydrogen selenide molecule
Names
IUPAC name Hydrogen selenide
Other names Hydroselenic acid selane selenium hydride
Identifiers
CAS Number	7783-07-5 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16503 Y
ChemSpider	518 Y
ECHA InfoCard	100.029.071
KEGG	C01528 Y
PubChem CID	533
RTECS number	X1050000
UNII	V91P54KPAM N
UN number	2202
CompTox Dashboard (EPA)	DTXSID20872822
SMILES [SeH2]
Properties
Chemical formula	H2Se
Molar mass	80.98 g/mol
Appearance	Colorless gas
Odor	decayed horseradish[1]
Density	3.553 g/dm3
Melting point	−65.73 °C (−86.31 °F; 207.42 K)
Boiling point	−41.25 °C (−42.25 °F; 231.90 K)
Solubility in water	0.70 g/100 mL
Solubility	soluble in CS2, phosgene
Vapor pressure	9.5 atm (21°C)[1]
Acidity (pKa)	3.89
Conjugate acid	Selenonium
Conjugate base	Selenide
Structure
Molecular shape	Bent
Hazards
EU classification	F+ T+ N
Main hazards	Extremely toxic and flammable
NFPA 704	4 4 0
R-phrases	R23/25, R33, R50/53
S-phrases	(S1/2), S20/21, S28, S45, S60, S61
Flash point	flammable gas
U.S. Permissible exposure limit (PEL)	TWA 0.05 ppm (0.2 mg/m3)[1]
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

Hydrogen selenide is a colorless gas that dissolves in water to make an acidic solution. It smells like rotten horseradish. It is very toxic. It burns easily, making selenium dioxide. It is similar to hydrogen sulfide, a gas that smells like rotten eggs. It is a strong reducing agent.

Preparation

Hydrogen selenide can be made by hydrolysis of aluminium selenide. This reaction also makes aluminium hydroxide. It can be made by reacting hydrogen with powdered selenium at a high temperature.

Uses

It can be used to add selenide ion to organic compounds. It can also be used to make selenium by reacting it with sulfur dioxide. This makes selenium, sulfur, and water.