Disulfur

HjCr.O, dichromic acid H2S2O7 disulfuric acid... 

HMn04 permanganic acid H2S2OS disulfurous acid... 

Nonmeta.ls, Sulfur reacts with fluorine to yield the remarkably stable sulfur hexafluoride, SF. Operating conditions must be controlled because a mixture of the lower fluorides such as disulfur difluoride [13709-35-8] 2 2 disulfur decafluoride [5714-22-7] 2 10 sulfur tetrafluoride [7783-60-0] SF4, may also be formed. When this reaction is carried out between 310 and 340°C, SF is primarily obtained and essentially no SF and only trace amounts of lower fluorides. Below 300°C, and preferably at ca 275°C, SF is the primary product. At 450—500°C, a mixture comprising ca 50% SF and the lower sulfur fluorides is formed (see Fluorine compounds, inorganic-sulfur). 

Disulfur Decafluoride. Disulfur decafluoride [5714-22-7] 2 10 extremely toxic, colorless, volatile Hquid (114). Electron diffraction... 

Disulfur decafluoride does not react rapidly with water, mercury, copper, or platinum at ambient temperatures. There is evidence that it slowly decomposes on various surfaces in the presence of water when stored in the vapor state (118). It is decomposed by molten KOH to give a mixture of potassium compounds of sulfur and fluorine. The gas reacts vigorously with many other metals and siUca at red heat (114). At ca 156°C it combines with CI2 or Br2 to form SF Cl or SF Br (119,120). At ca 200°C, S2F2Q is almost completely thermally decomposed into the hexa- and tetrafluoride (121). 

Chloroethyldisulfides are obtained by electrophilic attack on the sulfur atom of thiiranes by sulfenyl halides (Scheme 39). Sulfur dichloride and disulfur dichloride react similarly to give more sulfur-rich derivatives di- and tri-sulfenyl halides, and tri- and tetra-sulfides (Scheme 42). A 1 1 ratio of sulfur halide to thiirane gives the di- or tri-sulfenyl halide a 2 1 ratio the tri- or tetra-sulfide. Thiirane 1-oxides are cleaved by sulfenyl halides to thiolsulfinates (Scheme 43) (74JAP7440461). 

In 1960, Dann, Chiesa and Gates of the Kodak Research Laboratories found that the disulfur analog of then unknown 18-crown-6 resulted from the reaction shown in Eq. (6.3). Since the complexation properties of such substances were not yet recognized, especially as they might apply to transition metals, this early and pioneering work has not had the recognition it probably deserved. 

K. K. Pandey, Coordination Chemistry of Thionitr osyl, Thiazate, Disulfidothionitrute, Sulfur Monoxide and Disulfur Monoxide, Prog. Inorg. Chem., 40, 445 (1992). 

Disulfur decafluoride, S2F10, is obtained as a byproduct of the direct fluorination of sulfur to SFg but is somewhat tedious to separate and is more conveniently made by the photolytic reduction of SCIF5 (prepared as above) ... 

Like sulfurous acid , disulfurous acid is unknown either in the free state or in solution. However, as indicated in the preceding section, its salts, are readily obtained from concentrated solutions of hydrogen sulfite 2HS03 S2O52- + H2O. Unlike disulfates... 

Disulfur dichtoridc was added to an aqueous solution of ammonia to give a yellow precipitate of sulfur contaminated with S4N4 y. Pharm. Chim. 11, 315 (1835). 

It has a cyclic structure and may be regarded as a substituted diamide of disulfuric acid, H2S2O7 (Fig. 15.49b). 

Both sets of names are used in the literature. Free imidodisulfuric acid HN(S03H)2 (which is isoelectronic with disulfuric acid H2S2O7, p. 705) and free nitridotrisulfuric acid N(S03H)3 are unstable, but their salts are well characterized and have been extensively studied. 

Pyro-phosphorsaure, /. pyrophosphoric acid, -saure, /. pyro acid, -schleimsaure, /. pjto-mucic acid, furoic acid, -schwefelsaure, /. pyrosulfuric acid, disulfuric acid (H2S2O7). 

Disaccharides, 424 Discharge tube, 239, 255 Disproportionation, 361 Dissociation, 179 constant of HF, 361 Dissolving rate, 164 Distillation, 70 Disulfur dichloride, 103 Divalent, 282... 

A derivative 5 of the 1,3-dithiolopentathiepin system was obtained by the action of disulfur dichloride on the titanium complex 4 under conditions of high dilution.397... 

The parent compound 2 is obtained from thiophene-3,4-dithiol (1) and disulfur dichloride.400... 

The 8-cyano compound 2 is prepared by condensation of the disodium dithiolate 1 with disulfur dichloride.414... 

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