Nitrosonium tetrafluoroborate, also called nitrosyl tetrafluoroborate, is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbol ...

NOBF₄. This colourless solid is used in organic synthesis as a nitrosating agent. NOBF₄ is the nitrosonium salt of

fluoroboric acid Fluoroboric acid or tetrafluoroboric acid (archaically, fluoboric acid) is an inorganic compound with the chemical formula +BF4−], where H+ represents the solvated proton. The solvent can be any suitably Lewis-basic entity. For instance, in w ...

, and is composed of a nitrosonium cation, Osup>+, and a

tetrafluoroborate Tetrafluoroborate is the anion . This tetrahedral species is isoelectronic with tetrafluoroberyllate (), tetrafluoromethane (CF4), and tetrafluoroammonium () and is valence isoelectronic with many stable and important species including the perchlo ...

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

, F₄sup>−.

Reactions

The dominant property of NOBF₄ is the oxidizing power and electrophilic character of the nitrosonium cation. It forms colored

charge transfer complex In chemistry, a charge-transfer (CT) complex or electron-donor-acceptor complex describes a type of supramolecular assembly of two or more molecules or ions. The assembly consists of two molecules that self-attract through electrostatic forc ...

es with hexamethylbenzene and with

18-crown-6 18-Crown-6 is an organic compound with the formula 2H4Osub>6 and the IUPAC name of 1,4,7,10,13,16-hexaoxacyclooctadecane. It is a white, hygroscopic crystalline solid with a low melting point. Like other crown ethers, 18-crown-6 functions as a ...

. The latter, a deep yellow species, provides a means to dissolve NOBF₄ in dichloromethane. Nitrosonium tetrafluoroborate may be used to prepare metal salts of the type ^II(CH₃CN)_''x''F₄sub>2 (M = Cr, Mn, Fe, Co, Ni, Cu). The nitrosonium cation acts as the oxidizer, itself being reduced to nitric oxide gas: : M + 2NOBF₄ + ''x''CH₃CN → (CH₃CN)_''x''BF₄)₂ + 2NO With ferrocene the

ferrocenium tetrafluoroborate Ferrocenium tetrafluoroborate is an organometallic compound with the formula e(C5H5)2F4. This salt is composed of the cation e(C5H5)2sup>+ and the tetrafluoroborate anion (). The related hexafluorophosphate is also a popular reagent with simil ...

is formed.

References

Tetrafluoroborates Nitrosyl compounds {{inorganic-compound-stub