Disulfur difluoride

Disulfur difluoride
	Sulfur, S Fluorine, F
Names
	IUPAC name fluorosulfanyl thiohypofluorite
	Other names Difluorodisulfane
Identifiers
CAS Number	13709-35-8;
3D model (JSmol)	Interactive image;
ChemSpider	109926;
PubChem CID	123323;
CompTox Dashboard (EPA)	DTXSID60160058 ;
	InChI InChI=1S/F2S2/c1-3-4-2;
	SMILES FSSF;
Properties
Chemical formula	S2F2
Molar mass	102.127 g/mol
Melting point	−133 °C (−207 °F; 140 K)
Boiling point	15 °C (59 °F; 288 K)
Related compounds
Related compounds	O2F2; H2S2; S2Cl2; S2Br2; S2I2; SF2;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

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Disulfur difluoride is an inorganic compound with the chemical formula S₂F₂. It is a halide of sulfur.

Structure

Disulfur difluoride has a chain structure F−S−S−F. The angle between the F^a−S−S and S−S−F^b planes is 87.9°, while the angles of F^a−S−S and S−S−F^b are equivalent, and are equal to 108.3°. Both S−F bonds are equivalent and their length is 163.5 pm, while the length of the S−S bond is 189 pm. This structure is referred to as gauche, and is similar to H₂O₂.

There is a branched isomer of disulfur difluoride, thiothionyl fluoride, with the structure S=SF₂.

Synthesis

Silver(II) fluoride can fluorinate sulfur in a strictly dry container at 125 °C (257 °F; 398 K), and the reaction produces FS−SF:^[2]

S₈ + 8 AgF₂ → 4 S₂F₂ + 8 AgF

Reactions

Disulfur difluoride undergoes intramolecular rearrangement in the presence of fluorides of alkali metals, yielding the isomer S=SF₂:^[3]

FS−SF → S=SF₂

Decomposing to sulfur tetrafluoride and sulfur when heated to 180 °C:

2 S₂F₂ → SF₄ + 3 S

Hydrolysis:

2 S₂F₂ + 2 H₂O → SO₂ + 3 S + 4 HF

Reacting with sulfuric acid at 80 °C:

S₂F₂ + 3 H₂SO₄ → 5 SO₂ + 2 HF + 2 H₂O

Reacting with sodium hydroxide:

2 S₂F₂ + 6 NaOH → Na₂SO₃ + 3 S + 4 NaF + 3 H₂O

Reacting with oxygen at high pressure, using nitrogen dioxide as a catalyst:

2 S₂F₂ + 5 O₂ → SOF₄ + 3 SO₃^[4]^[5]^[6]

References

^ "Difluorodisulfane".
^ Davis, R.Wellington; Firth, Steven (1991). "The microwave spectrum of the chain isomer of disulfur difluoride: FS-SF". Journal of Molecular Spectroscopy. 145 (2): 225. doi:10.1016/0022-2852(91)90109-N.
^ Davis, R.Wellington (1986). "The microwave spectrum of the pyramidal isomer of disulfur difluoride: S=SF2". Journal of Molecular Spectroscopy. 116 (2): 371–383. doi:10.1016/0022-2852(86)90134-7.
^ Справочник химика / Редкол.: Никольский Б.П. и др.. — 3-е изд., испр. — Л.: Химия, 1971. — Т. 2. — 1168 с. (in Russian)
^ Химическая энциклопедия / Редкол.: Кнунянц И.Л. и др.. — М.: Советская энциклопедия, 1995. — Т. 4. — 639 с. — ISBN 978-5-85270-092-6 (in Russian)
^ 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 Russian)

[pubchem-1] "Difluorodisulfane".

[2] Davis, R.Wellington; Firth, Steven (1991). "The microwave spectrum of the chain isomer of disulfur difluoride: FS-SF". Journal of Molecular Spectroscopy. 145 (2): 225. doi:10.1016/0022-2852(91)90109-N.

[3] Davis, R.Wellington (1986). "The microwave spectrum of the pyramidal isomer of disulfur difluoride: S=SF2". Journal of Molecular Spectroscopy. 116 (2): 371–383. doi:10.1016/0022-2852(86)90134-7.

[4] Справочник химика / Редкол.: Никольский Б.П. и др.. — 3-е изд., испр. — Л.: Химия, 1971. — Т. 2. — 1168 с. (in Russian)

[5] Химическая энциклопедия / Редкол.: Кнунянц И.Л. и др.. — М.: Советская энциклопедия, 1995. — Т. 4. — 639 с. — ISBN 978-5-85270-092-6 (in Russian)

[6] 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 Russian)

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