NOCl

Nitrosyl chloride, with the chemical formula NOCl, is a reactive nitrosylating agent composed of a nitrosyl group bound to chlorine. It is a volatile and moisture-sensitive species used primarily in organic synthesis to introduce nitroso functionality or to generate related nitrosylating species.

Synthesis and occurrence: In laboratory settings, NOCl is commonly prepared by the reaction of nitric oxide with chlorine gas: 2 NO + Cl2 → 2 NOCl. It can also be generated in situ from other nitrosyl and chlorine-containing precursors as needed. Because of its reactivity with water, NOCl is typically handled under dry conditions and stored away from moisture and incompatible materials.

Structure and properties: NOCl is a triatomic molecule that is typically described as a covalent compound with N–O and N–Cl linkages. It is highly reactive and tends to exist as a gas at room temperature, though it can be condensed to a liquid under appropriate conditions. The compound readily reacts with moisture in the air and with many organic substrates, and it is sensitive to light, which can promote decomposition.

Reactions and uses: NOCl functions as a nitrosating agent, transferring the nitroso group to amines and other nucleophiles to form N-nitrosamines and related species. It can also participate in other nitrosylation reactions and serve as a precursor to various nitrosyl and chlorine-containing reagents used in synthesis. Its reactivity makes it a useful but handling-intensive reagent in specialized chemical workflows.

Safety and handling: NOCl is corrosive and toxic. It reacts violently with water, releasing acidic gases such as HCl and reactive nitrogen oxides. It can irritate the eyes, skin, and respiratory tract. Handling requires dry, inert or well-ventilated conditions, appropriate protective equipment, and strict incompatibility controls to prevent contact with moisture and organic materials.