Gas-phase structure | |
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Names | |
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IUPAC name Hypofluorous acid | |
Other names
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Identifiers | |
3D model (JSmol) | |
ChemSpider | |
PubChem CID | |
CompTox Dashboard (EPA) | |
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Properties | |
HOF | |
Molar mass | 36.0057 g/mol |
Appearance | pale yellow liquid above −117 °C white solid below −117 °C |
Melting point | −117 °C (−179 °F; 156 K) |
Boiling point | decomposes at 0 °C (32 °F; 273 K)[ citation needed ] |
Structure | |
Cs | |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | Explosive, strong oxidizer, corrosive |
NFPA 704 (fire diamond) | |
Related compounds | |
Other cations | Lithium hypofluorite |
Related compounds | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Hypofluorous acid, chemical formula H O F , is the only known oxyacid of fluorine and the only known oxoacid in which the main atom gains electrons from oxygen to create a negative oxidation state. The oxidation state of the oxygen in this acid (and in the hypofluorite ion OF− and in its salts called hypofluorites) is 0, while its valence is 2. It is also the only hypohalous acid that can be isolated as a solid. HOF is an intermediate in the oxidation of water by fluorine, which produces hydrogen fluoride, oxygen difluoride, hydrogen peroxide, ozone and oxygen. HOF is explosive at room temperature, forming HF and O2: [1]
This reaction is catalyzed by water. [2]
It was isolated in the pure form by passing F2 gas over ice at −40 °C, rapidly collecting the HOF gas away from the ice, and condensing it: [2]
The compound has been characterized in the solid phase by X-ray crystallography [1] as a bent molecule with an angle of 101°. The O–F and O–H bond lengths are 144.2 and 96.4 picometres, respectively. The solid framework consists of chains with O–H···O linkages. The structure has also been analyzed in the gas phase, a state in which the H–O–F bond angle is slightly narrower (97.2°).
Thiophene chemists commonly call a solution of hypofluorous acid in acetonitrile (generated in situ by passing gaseous fluorine through water in acetonitrile) Rozen's reagent. [3]
Hypofluorites are formally derivatives of OF−, which is the conjugate base of hypofluorous acid. One example is trifluoromethyl hypofluorite (CF3OF), which is a trifluoromethyl ester of hypofluorous acid. The conjugate base is known in salts such as lithium hypofluorite.
Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide salt and occurs naturally as the rare mineral carobbiite. Solutions of KF will etch glass due to the formation of soluble fluorosilicates, although HF is more effective.
Bromine trifluoride is an interhalogen compound with the formula BrF3. At room temperature, it is a straw-coloured liquid with a pungent odor which decomposes violently on contact with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent. It is used to produce uranium hexafluoride (UF6) in the processing and reprocessing of nuclear fuel.
Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. It is a structural analogue of acetic acid with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms and is a colorless liquid with a vinegar-like odor.
Cobalt(III) fluoride is the inorganic compound with the formula CoF3. Hydrates are also known. The anhydrous compound is a hygroscopic brown solid. It is used to synthesize organofluorine compounds.
Hexafluorosilicic acid is an inorganic compound with the chemical formula H
2SiF
6. Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.
Xenon difluoride is a powerful fluorinating agent with the chemical formula XeF
2, and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with water vapor, but is otherwise stable in storage. Xenon difluoride is a dense, colourless crystalline solid.
Titanium(IV) fluoride is the inorganic compound with the formula TiF4. It is a white hygroscopic solid. In contrast to the other tetrahalides of titanium, it adopts a polymeric structure. In common with the other tetrahalides, TiF4 is a strong Lewis acid.
Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, refrigerants, and reagents in catalysis. In addition to these applications, some organofluorine compounds are pollutants because of their contributions to ozone depletion, global warming, bioaccumulation, and toxicity. The area of organofluorine chemistry often requires special techniques associated with the handling of fluorinating agents.
The dioxygenyl ion, O+
2, is a rarely-encountered oxycation in which both oxygen atoms have a formal oxidation state of +1/2. It is formally derived from oxygen by the removal of an electron:
Fluoroboric acid or tetrafluoroboric acid is an inorganic compound with the simplified chemical formula H+[BF4]−. Unlike other strong acids like H2SO4 or HClO4, the pure tetrafluoroboric acid does not exist. The term "fluoroboric acid" refers to a range of chemical compounds, depending on the solvent. The H+ in the simplified formula of fluoroboric acid represents the solvated proton. The solvent can be any suitable Lewis base. For instance, if the solvent is water, fluoroboric acid can be represented by the formula [H3O]+[BF4]−, although more realistically, several water molecules solvate the proton: [H(H2O)n]+[BF4]−. The ethyl ether solvate is also commercially available, where the fluoroboric acid can be represented by the formula [H( 2O)n]+[BF4]−, where n is most likely 2.
The tetrafluoroammonium cation is a positively charged polyatomic ion with chemical formula NF+
4. It is equivalent to the ammonium ion where the hydrogen atoms surrounding the central nitrogen atom have been replaced by fluorine. Tetrafluoroammonium ion is isoelectronic with tetrafluoromethane CF
4, trifluoramine oxide ONF
3 and the tetrafluoroborate BF−
4 anion.
Fluorination by sulfur tetrafluoride produces organofluorine compounds from oxygen-containing organic functional groups using sulfur tetrafluoride. The reaction has broad scope, and SF4 is an inexpensive reagent. It is however hazardous gas whose handling requires specialized apparatus. Thus, for many laboratory scale fluorinations diethylaminosulfur trifluoride ("DAST") is used instead.
Electrophilic fluorination is the combination of a carbon-centered nucleophile with an electrophilic source of fluorine to afford organofluorine compounds. Although elemental fluorine and reagents incorporating an oxygen-fluorine bond can be used for this purpose, they have largely been replaced by reagents containing a nitrogen-fluorine bond.
Chromyl fluoride is an inorganic compound with the formula CrO2F2. It is a violet-red colored crystalline solid that melts to an orange-red liquid.
Fluorine nitrate is an unstable derivative of nitric acid with the formula FNO
3. It is shock-sensitive. Due to its instability, it is often produced from chlorine nitrate as needed. Fluorine Nitrate is an inert molecule thought to play a significant role in atmospheric chemistry.
Trifluoromethyl hypofluorite is an organofluorine compound with the chemical formula CF3OF. It exists as a colorless gas at room temperature and is highly toxic. It is a rare example of a hypofluorite. It can be seen as a similar chemical compound to methanol where every hydrogen atom is replaced by a fluorine atom. It is a trifluoromethyl ester of hypofluorous acid. It is prepared by the reaction of fluorine gas with carbon monoxide:
Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.
Radical fluorination is a type of fluorination reaction, complementary to nucleophilic and electrophilic approaches. It involves the reaction of an independently generated carbon-centered radical with an atomic fluorine source and yields an organofluorine compound.
Trifluoroperacetic acid is an organofluorine compound, the peroxy acid analog of trifluoroacetic acid, with the condensed structural formula CF
3COOOH. It is a strong oxidizing agent for organic oxidation reactions, such as in Baeyer–Villiger oxidations of ketones. It is the most reactive of the organic peroxy acids, allowing it to successfully oxidise relatively unreactive alkenes to epoxides where other peroxy acids are ineffective. It can also oxidise the chalcogens in some functional groups, such as by transforming selenoethers to selones. It is a potentially explosive material and is not commercially available, but it can be quickly prepared as needed. Its use as a laboratory reagent was pioneered and developed by William D. Emmons.
Peroxymonophosphoric acid is an oxyacid of phosphorus. It is a colorless viscous oil. Its salts are called peroxymonophosphates. Another peroxyphosphoric acid is peroxydiphosphoric acid, H4P2O8.