Nitrosylsulfuric acid

Nitrosylsulfuric acid
IUPAC name Nitrosylsulfuric acid
Other names nitrosonium bisulfate, chamber crystals
Identifiers
CAS number	7782-78-7
PubChem	82157
ChemSpider	74147 Y
Jmol-3D images	Image 1
SMILES O=NOS(=O)(=O)O
InChI InChI=1S/HNO5S/c2-1-6-7(3,4)5/h(H,3,4,5) Y Key: VQTGUFBGYOIUFS-UHFFFAOYSA-N Y InChI=1/HNO5S/c2-1-6-7(3,4)5/h(H,3,4,5) Key: VQTGUFBGYOIUFS-UHFFFAOYAM
Properties
Molecular formula	HNO5S
Molar mass	127.08 g/mol
Appearance	pale yellow crystals
Density	1.612 g/mL in 40% sulfuric acid soln
Melting point	73.5 °C
Boiling point	decomposes
Solubility in water	decomposes
Solubility	soluble in H2SO4
Hazards
Main hazards	oxidizer
Related compounds
Other anions	NOCl
Other cations	NaHSO4
Related compounds	NOBF4
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Nitrosylsulfuric acid is the chemical compound with the formula NOHSO₄.

This salt is a source of the NO⁺ ion, It can also be viewed as the mixed acid anhydride of sulfuric acid and nitrous acid:

HNO₂ + H₂SO₄ → NOHSO₄ +H₂O

NOHSO₄ is useful in organic chemistry to prepare diazonium salts from amines. A typical procedure entails dissolving sodium nitrite in concentrated sulfuric acid in an ice bath.

Related NO-delivery reagents include nitrosonium tetrafluoroborate, [NO]BF₄, and nitrosyl chloride.