Nitroxylic acid or hydronitrous acid is an unstable reduced oxonitrogen acid. It has formula H₄N₂O₄ containing nitrogen in the +2 oxidation state. It consists of a central pair of bonded

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

atoms with four

hydroxyl groups In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

around them, giving rise to

hydrazine Hydrazine is an inorganic compound with the chemical formula . It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydraz ...

-1,1,2,2-tetrol as an alternate chemical name. The corresponding anion called nitroxylate is ; its

empirical formula In chemistry, the empirical formula of a chemical compound is the simplest whole number ratio of atoms present in a compound. A simple example of this concept is that the empirical formula of sulfur monoxide, or SO, is simply SO, as is the empir ...

is the basis for the original names of some of its

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

s. The first clue that nitroxylic acid exists was when Edward Bedford Maxted electrolysed

sodium nitrite Sodium nitrite is an inorganic compound with the chemical formula . It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite sa ...

dissolved in

liquid ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the formula . A stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pungent smell. It is widely used in fertilizers, ...

. A bright yellow substance deposited on the cathode. He called this ''disodium nitrite''. The disodium nitrite could also be made by mixing ammonia solutions of sodium and sodium nitrite in the complete absence of water. Disodium nitrite reacts with water to form sodium nitrite,

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

and

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

. Other ways to make the disodium nitrite include reacting sodium with

ammonium nitrate Ammonium nitrate is a chemical compound with the formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, but does not form hydrates. It is predominantly us ...

or electrolysing

sodium nitrate Sodium nitrate is the chemical compound with the chemical formula, formula . This alkali metal nitrate salt (chemistry), salt is also known as Chile saltpeter (large deposits of which were historically mined in Chile) to distinguish it from ordi ...

solution. The substance is called sodium nitroxylate by current

systematic nomenclature Chemical nomenclature is a set of rules to generate systematic names for chemical compounds. The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry (IUPAC). IUPAC ...

rules. Disodium nitrite is very unstable and experimenters often had their apparatus destroyed when making it. Disodium nitrite reacts with oxygen and carbon dioxide explosively. Lithium sodium nitroxylate LiNaNO₂ also exists and explodes at 130 °C. The parent compound, nitroxylic acid, might be produced when

nitrous acid Nitrous acid (molecular formula ) is a weak and monoprotic acid known only in solution, in the gas phase, and in the form of nitrite () salts. It was discovered by Carl Wilhelm Scheele, who called it " phlogisticated acid of niter". Nitrous ac ...

is reduced by the Eu²⁺ ion.

References

{{Nitrogen compounds Nitrogen oxoacids