Sulfur difluoride

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| IUPACName = sulfoxylic difluoride

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|Section1={{Chembox Identifiers

| CASNo = 13814-25-0

| PubChem = 139605

| ChemSpiderID = 123122

| SMILES = FSF

| InChI = InChI=1S/F2S/c1-3-2

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|Section2={{Chembox Properties

| Formula = SF₂

| MolarMass = 70.062 g/mol

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|Section3={{Chembox Hazards

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Sulfur difluoride is an inorganic compound with the chemical formula SF₂. It can be generated by the reaction of sulfur dichloride and potassium fluoride or mercury(II) fluoride at low pressures:

:SCl₂ + 2 KF → SF₂ + 2 KCl

:SCl₂ + HgF₂ → SF₂ + HgCl₂

The F−S−F bond angle is 98°, and the length of S−F bond is 159 pm.{{cite journal|doi=10.1126/science.164.3882.950|title=Microwave Spectrum and Structure of Sulfur Difluoride|year=1969|last1=Johnson|first1=D. R.|last2=Powell|first2=F. X.|journal=Science|volume=164|issue=3882|pages=950–1|pmid=17775599|bibcode=1969Sci...164..950J |s2cid=46046291 }} The compound is highly unstable, dimerising to FSSF₃. This unsymmetrical isomer of S₂F₄ is proposed to arise via insertion of SF₂ into the S−F bond of a second molecule SF₂:{{Greenwood&Earnshaw}}

It can also be formed from oxygen difluoride and hydrogen sulfide:{{cn|date=April 2022}}

:OF₂ + H₂S → SF₂ + H₂O