Difluorodisulfanedifluoride

Last updated
difluorodisulfanedifluoride
Disulfur-tetrafluoride-3D-balls.png
Names
IUPAC name
1,1,1,2-tetrafluoro-1λ4-disulfane
Other names
1,2-difluorodisulfane 1,1-difluoride
Identifiers
3D model (JSmol)
ChemSpider
PubChem CID
  • [1] :InChI=1S/F4S2/c1-5-6(2,3)4
    Key: MKKRFYJAWNGNCJ-UHFFFAOYSA-N
  • S(SF)(F)(F)F
Properties
S2F4
Molar mass 140.124 g/mol [1]
Appearanceliquid
Density 1.81 [2]
Melting point −98 °C (−144 °F; 175 K) [2]
Boiling point 39 °C (102 °F; 312 K) [2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

1,1,1,2-tetrafluorodisulfane, also known as 1,2-difluorodisulfane 1,1-difluoride or just difluorodisulfanedifluoride (FSSF3) is an unstable molecular compound of fluorine and sulfur. The molecule has a pair of sulfur atoms, with one fluorine atom on one sulfur, and three fluorine atoms on the other. It has the uncommon property that all the bond lengths are different. [3] The bond strength is not correlated with bond length but is inversely correlated with the force constant (Badger's rule). [3] The molecule can be considered as sulfur tetrafluoride in which a sulfur atom is inserted into a S-F bond. [3]

Contents

Atoms are labelled with the sulfur atom connected to three fluorine atoms as Shyp (for hypervalent) and Stop. The fluorine atoms are labelled Ftop attached to Stop, and on the hypervalent S atom: Fcis, the closest F atom to Ftop, Ftrans the furthest away F atom from Ftop, and Feq [3]

Carlowitz first determined the structure in 1983. [3]

atom 1atom 2 bond length Å [3] bond dissociation energy
kcal/mol [3] 		bond angle to S-S axis ° [4]
FtopStop1.6286.4105
FcisShyp1.67102.176
FtransShyp1.7797.892
FeqShyp1.6086.7106
StopShyp2.08

Feq is 90° from Ftrans, and 84° from Fcis, and the torsion compared to Ftop is about 95°. [4]

Reactions

The dimerization reaction 2SF2⇌ FSSF3 is reversible. [5] It also disproportionates: SF2 + FSSF3 → FSSF + SF4. [5] A side reaction also produces the intermediate F3SSSF3. [6] hydrogen fluoride catalyses disproportionation to sulfur and sulfur tetrafluoride by forming a reactive intermediate HSF molecule. [7] When FSSF3 dissociates, the Fcis atom forms a new bond to the Stop atom, and the S-S bond breaks. [3] As a gas, at ambient and totally clean conditions, FSSF3 decomposes with a half life of about 10 hours. Disproportionation to SSF2 and SF4 catalysed by metal fluorides can take place in under one second. However it is indefinitely stable at -196 °C. [4]

A symmetrical molecule F2SSF2 is calculated to be 15.1 kcal/mol higher in energy than FSSF3. [3]

FSSF3 is easily hydrolysed with water. [8]

FSSF3 spontaneously reacts with oxygen gas to make thionyl fluoride, the only sulfur fluoride that does not need any assistance to do this. [8] FSSF3 reacts with copper at high temperatures producing copper fluoride and copper sulfide. [8]

Formation

SF3SF can be made in the laboratory when low pressure (10 mm Hg) SCl2 vapour is passed over potassium fluoride or mercuric fluoride heated to 150 °C. Byproducts include FSSF, SSF2, SF4, SF3SCl, and FSSCl. [8] SF3SCl can be removed from this mixture in a reaction with mercury. [8] Separation of the sulfur fluorides can be achieved by low temperature distillation. SF3SF distills just above -50 °C. [9]

SF3SF is also made in small amounts by reacting sulfur with silver fluoride, or photolysis of disulfur difluoride and SSF2. [8] The molecule is formed by the dimerization of sulfur difluoride. [3]

Properties

The nuclear magnetic resonance spectrum of FSSF3 shows four bands, each of eight lines at -53.2, -5.7, 26.3 and 204.1 ppm. [5]

FSSF3 is stable as a solid, as a liquid below -74 °C and dissolved in other sulfur fluoride liquids. [8] This is in contrast to SF2 which is only stable as a dilute gas. [8]

Infrared vibration bands for FSSF3 are at 810, 678, 530, 725, and 618(S-S) cm−1. [8]

The related compound FSSSF3 has a similar structure, but with an extra sulfur atom in the chain. Thiothionyltetrafluoride, S=SF4 may exist as a gas. It is less energetically favourable to FSSF3 by 37 kJ/mol, but has a high energy barrier of 267 kJ/mol. [10] However it may disproportionate rapidly to sulfur and sulfur tetrafluoride. [10] The other known sulfur fluorides are sulfur difluoride, sulfur tetrafluoride, sulfur hexafluoride, disulfur decafluoride, disulfur difluoride and thiothionyl fluoride, difluorotrisulfane, and difluorotetrasulfane. [10] The Ftop atom can be substituted with Cl to yield ClSSF3 (2-chloro-1,1,1-trifluorodisulfane). [5]

Related Research Articles

<span class="mw-page-title-main">Oxygen difluoride</span> Chemical compound

Oxygen difluoride is a chemical compound with the formula OF2. As predicted by VSEPR theory, the molecule adopts a "bent" molecular geometry. It is strong oxidizer and has attracted attention in rocketry for this reason. With a boiling point of -144.75 °C, OF2 is the most volatile (isolable) triatomic compound. The compound is one of many known oxygen fluorides.

The 3-center 4-electron (3c–4e) bond is a model used to explain bonding in certain hypervalent molecules such as tetratomic and hexatomic interhalogen compounds, sulfur tetrafluoride, the xenon fluorides, and the bifluoride ion. It is also known as the Pimentel–Rundle three-center model after the work published by George C. Pimentel in 1951, which built on concepts developed earlier by Robert E. Rundle for electron-deficient bonding. An extended version of this model is used to describe the whole class of hypervalent molecules such as phosphorus pentafluoride and sulfur hexafluoride as well as multi-center π-bonding such as ozone and sulfur trioxide.

<span class="mw-page-title-main">Disulfur decafluoride</span> Chemical compound

Disulfur decafluoride is a chemical compound with the formula S2F10. It was discovered in 1934 by Denbigh and Whytlaw-Gray. Each sulfur atom of the S2F10 molecule is octahedral, and surrounded by five fluorine atoms and one sulfur atom. The two sulfur atoms are connected by a single bond. In the S2F10 molecule, the oxidation state of each sulfur atoms is +5, but their valency is 6. S2F10 is highly toxic, with toxicity four times that of phosgene.

<span class="mw-page-title-main">Xenon difluoride</span> Chemical compound

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.

<span class="mw-page-title-main">Sulfur tetrafluoride</span> Chemical compound

Sulfur tetrafluoride is the chemical compound with the formula SF4. It is a colorless corrosive gas that releases dangerous HF upon exposure to water or moisture. Despite these unwelcome characteristics, this compound is a useful reagent for the preparation of organofluorine compounds, some of which are important in the pharmaceutical and specialty chemical industries.

<span class="mw-page-title-main">Selenium tetrafluoride</span> Chemical compound

Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.

<span class="mw-page-title-main">Diethylaminosulfur trifluoride</span> Chemical compound

Diethylaminosulfur trifluoride (DAST) is the organosulfur compound with the formula Et2NSF3. This liquid is a fluorinating reagent used for the synthesis of organofluorine compounds. The compound is colourless; older samples assume an orange colour.

<span class="mw-page-title-main">Thiazyl fluoride</span> Chemical compound

Thiazyl fluoride, NSF, is a colourless, pungent gas at room temperature and condenses to a pale yellow liquid at 0.4 °C. Along with thiazyl trifluoride, NSF3, it is an important precursor to sulfur-nitrogen-fluorine compounds. It is notable for its extreme hygroscopicity.

Fluorination by sulfur tetrafluoride produces organofluorine compounds from oxidized organic compounds, including alcohols, carbonyl compounds, alkyl halides, and others.

Sulfur fluoride may refer to any of the following sulfur fluorides:

<span class="mw-page-title-main">Thionyl tetrafluoride</span> Chemical compound

Thionyl tetrafluoride, also known as sulfur tetrafluoride oxide, is an inorganic compound with the formula SOF4. It is a colorless gas.

<span class="mw-page-title-main">Vanadium pentafluoride</span> Chemical compound

Vanadium(V) fluoride is the inorganic compound with the chemical formula VF5. It is a colorless volatile liquid. It is a highly reactive compound, as indicated by its ability to fluorinate organic substances.

<span class="mw-page-title-main">Disulfur difluoride</span> Chemical compound

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

<span class="mw-page-title-main">Thiophosphoryl fluoride</span> Chemical compound

Thiophosphoryl fluoride is an inorganic molecular gas with formula PSF3 containing phosphorus, sulfur and fluorine. It spontaneously ignites in air and burns with a cool flame. The discoverers were able to have flames around their hands without discomfort, and called it "probably one of the coldest flames known". The gas was discovered in 1888.

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.

Difluoroamino sulfur pentafluoride is a gaseous chemical compound of fluorine, sulfur, and nitrogen. It is unusual in having a hexa-coordinated sulfur atom with a link to nitrogen. Other names for this substance include difluoro(pentafluorosulfur)amine, pentafluorosulfanyldifluoramine, and pentafluorosulfanyl N,N-difluoramine.

<span class="mw-page-title-main">1,3-Difluoro-trisulfane-1,1-difluoride</span> Chemical compound

1,3-Difluoro-trisulfane-1,1-difluoride is an inorganic molecular substance with the structure SF3SSF, consisting of sulfur in a low oxidation state with fluorine. The compound consists of a chain of three sulfur atoms, with three fluorine atoms bonded to the sulfur on one end and the fourth fluorine bonded to the sulfur on the other end. It has a melting point of -62 °C and a boiling point of 94 °C. As a gas, it is unstable and breaks up to form SSF2 and SF4.

Pentafluorosulfur hypofluorite is an oxyfluoride of sulfur in the +6 oxidation state, with a fluorine atom attached to oxygen. The formula is SOF6. In standard conditions it is a gas.

<span class="mw-page-title-main">Thiothionyl fluoride</span> Chemical compound

Thiothionyl fluoride is a chemical compound of fluorine and sulfur, with the chemical formula S=SF2. It is an isomer of disulfur difluoride (difluorodisulfane) F−S−S−F.

<span class="mw-page-title-main">Seleninyl fluoride</span> Chemical compound

Seleninyl fluoride is an oxyfluoride of selenium with the chemical formula SeOF2.

References

  1. 1 2 3 "Disulfane, 1,1,1,2-tetrafluoride". ChemIDplus. US National Library of Medicine.
  2. 1 2 3 Haas, A.; Willner, H. (March 1980). "Chalkogenfluoride in niedrigen Oxydationsstufen. IV. Darstellung und Charakterisierung von reinem S2F4". Zeitschrift für anorganische und allgemeine Chemie. 462 (1): 57–60. doi:10.1002/zaac.19804620107.
  3. 1 2 3 4 5 6 7 8 9 10 Lindquist, Beth Anne (2014). insights into the chemistry of sulfur-containing molecules (PDF) (Thesis). Urbana, Illinois.
  4. 1 2 3 Carlowitz, Michael V.; Oberhammer, Heinz; Willner, Helge; Boggs, James E. (July 1983). "Structural determination of a recalcitrant molecule (S2F4)". Journal of Molecular Structure. 100: 161–177. Bibcode:1983JMoSt.100..161C. doi:10.1016/0022-2860(83)90090-X.
  5. 1 2 3 4 Seel, Fritz; Budenz, Rudolf; Gombler, Willy (June 1970). "1.2-Difluor-disulfan-1.1-difluorid und 1-Fluor-2-chlor-disulfan-1.1-difluorid". Chemische Berichte. 103 (6): 1701–1708. doi:10.1002/cber.19701030606.
  6. ↑ Losking, O.; Willner, H. (1974). Lower sulfur fluorides. Advances in Inorganic Chemistry and Radiochemistry. Vol. 16. pp.  140–141. doi:10.1016/S0065-2792(08)60294-0. ISBN   9780120236169.
  7. ↑ Seel, F.; Stein, R. (October 1979). "Darstellung des 1,2-difluordisulfan-1,1-difluorids aus difluordisulfan in einer glimmentladung". Journal of Fluorine Chemistry (in German). 14 (4): 339–346. doi:10.1016/S0022-1139(00)82977-2.
  8. 1 2 3 4 5 6 7 8 9 Seel, F. (1974). Lower Sulfur Fluorides. Advances in Inorganic Chemistry and Radiochemistry. Vol. 16. pp.  297–333. doi:10.1016/S0065-2792(08)60294-0. ISBN   9780120236169.
  9. ↑ Seel, F.; Roth, J. (1984). "Untersuchung von Schwefel-Fluor-Verbindungen durch Codestillation und Cosublimation im Cady-Rohr". Fresenius' Zeitschrift für analytische Chemie (in German). 319 (8): 910–914. doi:10.1007/BF00487070. S2CID   101618324.
  10. 1 2 3 Steudel, Yana; Steudel, Ralf; Wong, Ming Wah; Lentz, Dieter (September 2001). "An ab initio MO Study of the Gas-Phase Reactions 2 SF2 → FS−SF3 → S=SF4 − Molecular Structures, Reaction Enthalpies and Activation Energies". European Journal of Inorganic Chemistry. 2001 (10): 2543–2548. doi:10.1002/1099-0682(200109)2001:10<2543::AID-EJIC2543>3.0.CO;2-6.

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