Nitrosylsulfuric acid

Nitrosylsulfuric acid
Names


IUPAC name Nitrosylsulfuric acid
Other names nitrosonium bisulfate, chamber crystals
Identifiers
CAS Number	7782-78-7^Y
3D model (Jmol)	Interactive image
ChemSpider	74147^Y
ECHA InfoCard	100.029.058
PubChem	82157
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
SMILES O=NOS(=O)(=O)O
Properties
Chemical 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 (164.3 °F; 346.6 K)
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
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y (what is ^YN ?)
Infobox references

Nitrosylsulfuric acid is the chemical compound with the formula NOHSO₄. It is a colourless solid that is used industrially in the production of caprolactam, and was formerly part of the lead chamber process for producing sulfuric acid.

A typical procedure entails dissolving sodium nitrite in concentrated sulfuric acid in an ice bath:

The molecule can also be viewed as the mixed anhydride of sulfuric acid and nitrous acid. Alternatively, it can be prepared by the reaction of nitric acid and sulfur dioxide.

NOHSO₄ is useful in organic chemistry to prepare diazonium salts from amines. Related NO-delivery reagents include nitrosonium tetrafluoroborate ([NO]BF₄) and nitrosyl chloride.