Disulfur difluoride
{{Chembox
| ImageFile = Disulfur-difluoride-2D-dimensions.png
| ImageFileL2 = Disulfur-difluoride-3D-balls.png
| ImageFileR2 = Disulfur-difluoride-3D-vdW.png
| ImageCaptionL2 = {{color box|yellow}} Sulfur, S;
{{color box|rgb(192,256,128)}} Fluorine, F
| IUPACName = fluorosulfanyl thiohypofluorite
| OtherNames = Difluorodisulfane{{cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/Difluorodisulfane | title=Difluorodisulfane }}
|Section1={{Chembox Identifiers
| CASNo = 13709-35-8
| PubChem = 123323
| ChemSpiderID = 109926
| SMILES = FSSF
| InChI = 1S/F2S2/c1-3-4-2
}}
|Section2={{Chembox Properties
| Formula = {{chem2|S2F2}}
| MolarMass = 102.127 g/mol
| Appearance =
| Density =
| MeltingPtC = −133
| BoilingPtC = 15
| Solubility =
}}
|Section3={{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
|Section8={{Chembox Related
| OtherCompounds = {{ubl|Dioxygen difluoride|Hydrogen disulfide|Disulfur dichloride|Disulfur dibromide|Disulfur diiodide|Sulfur difluoride}}
}}
}}
Disulfur difluoride is an inorganic compound with the chemical formula {{chem2|S2F2|auto=1}}. It is a halide of sulfur.
Structure
Disulfur difluoride has a chain structure {{chem2|F\sS\sS\sF}}. The angle between the {{chem2|F^{a}\sS\sS}} and {{chem2|S\sS\sF^{b}|}} planes is 87.9°, while the angles of {{chem2|F^{a}\sS\sS}} and {{chem2|S\sS\sF^{b}|}} are equivalent, and are equal to 108.3°. Both {{chem2|S\sF}} bonds are equivalent and their length is 163.5 pm, while the length of the {{chem2|S\sS}} bond is 189 pm. This structure is referred to as gauche, and is similar to Hydrogen peroxide.
There is a branched isomer of disulfur difluoride, thiothionyl fluoride, with the structure {{chem2|S\dSF2}}.
Synthesis
Silver(II) fluoride can fluorinate sulfur in a strictly dry container at {{cvt|125|C|F K}}, and the reaction produces {{chem2|FS\sSF}}:{{cite journal|doi=10.1016/0022-2852(91)90109-N|title=The microwave spectrum of the chain isomer of disulfur difluoride: FS-SF|year=1991|last1=Davis|first1=R.Wellington|last2=Firth|first2=Steven|journal=Journal of Molecular Spectroscopy|volume=145|issue=2|pages=225}}
Reactions
Disulfur difluoride undergoes intramolecular rearrangement in the presence of fluorides of alkali metals, yielding the isomer S=SF2:{{cite journal|doi=10.1016/0022-2852(86)90134-7|title=The microwave spectrum of the pyramidal isomer of disulfur difluoride: S=SF2|year=1986|last1=Davis|first1=R.Wellington|journal=Journal of Molecular Spectroscopy|volume=116|issue=2|pages=371–383}}
:{{chem2|FS\sSF → S\dSF2}}
- Decomposing to sulfur tetrafluoride and sulfur when heated to 180 °C:
:{{chem2|2 S2F2 → SF4 + 3 S}}
:{{chem2|2 S2F2 + 2 H2O → SO2 + 3 S + 4 HF}}
- Reacting with sulfuric acid at 80 °C:
:{{chem2|S2F2 + 3 H2SO4 → 5 SO2 + 2 HF + 2 H2O}}
- Reacting with sodium hydroxide:
:{{chem2|2 S2F2 + 6 NaOH → Na2SO3 + 3 S + 4 NaF + 3 H2O}}
- Reacting with oxygen at high pressure, using nitrogen dioxide as a catalyst:
:{{chem2|2 S2F2 + 5 O2 → SOF4 + 3 SO3}}Справочник химика / Редкол.: Никольский Б.П. и др.. — 3-е изд., испр. — Л.: Химия, 1971. — Т. 2. — 1168 с. {{in lang|ru}}Химическая энциклопедия / Редкол.: Кнунянц И.Л. и др.. — М.: Советская энциклопедия, 1995. — Т. 4. — 639 с. — {{ISBN|978-5-85270-092-6}} {{in lang|ru}}Лидин Р.А. и др. Химические свойства неорганических веществ: Учеб. пособие для вузов. — 3-е изд., испр. — М.: Химия, 2000. — 480 с. — {{ISBN|978-5-7245-1163-6}} {{in lang|ru}}