Nitrosyl chloride

Nitrosyl chloride

Names
IUPAC name Nitrosyl chloride
Other names Nitrogen chloride oxide Nitrogen oxychloride Nitrosonium chloride Tildens Reagent
Properties
Chemical formula	NOCl
Molar mass	65.459 g/mol
Appearance	Yellow or reddish gas
Odor	Choking
Density	2.872 g/cm3 1.36 g/cm3 (-5.7 °C)
Melting point	−59.4 °C (−74.9 °F; 213.8 K)
Boiling point	−5.55 °C (22.01 °F; 267.60 K)
Solubility in water	Reacts
Solubility	Reacts with alcohols Soluble in oleum
Vapor pressure	2,409 mmHg at 25 °C
Thermochemistry
Std molar entropy (So298)	261.68 J·K−1·mol−1
Std enthalpy of formation (ΔfHo298)	51.71 kJ/mol
Hazards
Safety data sheet	Matheson
Flash point	Non-flammable
Related compounds
Related compounds	Nitryl chloride Nitrogen dioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Nitrosyl chloride is a yellow gas, commonly encountered as a decomposition product of aqua regia, very corrosive and toxic. It has the chemical formula NOCl.

Due to its hazards, nitrosyl chloride doesn't have many uses in amateur chemistry, and most of the time it's encountered as unwanted side-product in chemical reactions, such as the preparation of aqua regia.

Properties

Chemical

Nitrosyl chloride reacts with water to give hydrochloric acid and nitrogen oxides.

Physical

Nitrosyl chloride is a yellowish gas, which reacts with water.

Availability

Nitrosyl chloride is sold by industrial suppliers, but they will not sell it to individuals due to its hazards. Not even big chemical suppliers have it in their stock.

Preparation

There are several routes to nitrosyl chloride:

The most common route involves the reaction between nitric oxide and chlorine, below 100 °C. Above this temperature, the reaction reverses.

2 NO + Cl₂ → 2 NOCl

Dehydration of nitrous acid by using hydrochloric acid will give nitrosyl chloride:

HNO₂ + HCl → NOCl + H₂O

Nitrosyl chloride is an unwanted side product in the preparation of aqua regia.

Projects

• Make nitrosylsulfuric acid
• Make N-nitroso compounds

Handling

Safety

Nitrosyl chloride is a toxic and corrosive gas. Work should be performed in a well ventilated area or outside.

Nitrosyl chloride reacts violently and may even explode in contact with ethers or ketones in the presence of trace metal salts.

Storage

Nitrosyl chloride should not be stored unless you have gas cylinders specially designed to store this compound.

It's best to use this compound as soon as you made it.

Disposal

Nitrosyl chloride can be neutralized by bubbling it in an aqueous alkaline solution.

References

Relevant Sciencemadness threads

• nitrosyl chloride, NOCl, removal!
• NOCl as chlorinating/nitrating agent?