Chemistry: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
InChI InChI=1S/F2S2/c1-3-4-2
SMILES FSSF
Properties
Chemical formula	S 2F 2
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	O 2F 2 H 2S 2 S 2Cl 2 S 2Br 2 S 2I 2 SF 2
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Disulfur difluoride is an inorganic compound with the chemical formula S
2F
2. It is a halide of sulfur.

Structure

Disulfur difluoride has a chain structure F–S–S–F. The angle between the Fa
–S–S and S–S–Fb
planes is 87.9°, while the angles of Fa
–S–S and S–S–Fb
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 H
2O
2.

There is a branched isomer of disulfur difluoride, thiothionyl fluoride, with the structure S=SF
2.

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:

S
8 + 8 AgF
2 → 4 S
2F
2 + 8 AgF

Reactions

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

FS–SF → S=SF
2

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

2 S
2F
2 → SF
4 + 3 S

• Hydrolysis:

2 S
2F
2 + 2 H
2O → SO
2 + 3 S + 4 HF

• Reacting with sulfuric acid at 80 °C:

S
2F
2 + 3 H
2SO
4 → 5 SO
2 + 2 HF + 2 H
2O

• Reacting with sodium hydroxide:

2 S
2F
2 + 6 NaOH → Na
2SO
3 + 3 S + 4 NaF + 3 H
2O

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

2 S
2F
2 + 5 O
2 → SOF
4 + 3 SO
3