Sulfur forms

Molybdenite concentrate contains about 90% M0S2. The remainder is primarily siUca, with lesser amounts of Fe, Al, and Cu. The concentrate is roasted to convert the sulfide to technical molybdic oxide. Molybdenum is added to steel in the form of this oxide. In modem molybdenum conversion plants, the oxidized sulfur formed by roasting M0S2 is converted to sulfuric acid. 

The use of alkali or alkaline-earth sulfides cataly2es the reaction so that it is complete in a few hours at 150—160°C use of aluminum chloride as the catalyst gives a comparable reaction rate at 115°C. When an excess of sulfur is used, the product can be distilled out of the reactor, and the residue of sulfur forms part of the charge in the following batch reaction. The reaction is carried out in a stainless steel autoclave, and the yield is better than 98% based on either reactant. Phosphoms sulfochloride is used primarily in the manufacture of insecticides (53—55), such as Parathion. 

When heated to 100°C, silver oxide decomposes into its elements, and is completely decomposed above 300°C. Silver oxide and sulfur form silver sulfide. Silver oxide absorbs carbon dioxide from the air, forming silver carbonate. 

Sulfur forms several series of haUdes with all of the halogens except iodine. The fluorides include the commercially important sulfur hexafluoride [2551-62-4] (see Fluorine compounds, inorganic). 

Severe concentration cell corrosion involves segregation of aggressive anions beneath deposits. Concentrations of sulfate and chloride, in particular, are deleterious. Acid conditions may be established beneath deposits as aggressive anions segregate to these shielded regions. Mineral acids, such as hydrochloric and sulfuric, form by hydrolysis. The mechanism of acid formation is discussed in Chap. 2. 

As long a column of liquid as possible is used to overcome the tendency for steam to work back up the inlet tube. If this happens, the sulfur formed is likely to clog the tube. This can be avoided by proper manipulation of the stopcock J. 

Sulfur forms two main series of oxohalides, the thionyl dihalides OS X2 and the sulfuryl dihalides 02S X2. In addition, various other oxofluorides and peroxofluorides are known (p. 688). Thionyl fluorides and chlorides are colourless volatile liquids (Table 15.14) OSBt2 is rather less volatile and is orange-coloured. 

Tlie thermal reaction of dithiiranes is of particular interest in relation with the dithiirane/thioketone 5-sulfide manifold. Heating 5-oxodithiiranes (4) in solution led to both isomerization to 6,7-dithia-8-oxabicyclo[3.2.1]-octanes 74 and desulfurization to 5-oxothiones 75, the ratio of which was dependent on the reaction conditions employed. The intramolecular [3 + 2] cycloaddition of the thioketone 5-sulfide 76, generated by ring-opening, provides a straightforward explanation for the formation of 74. Meanwhile, 75 is probably formed by a nucleophilic attack on the sulfur atom by another molecule of 4 and/or by elemental sulfur formed during the reaction. 

A crude oil burned in electrical generating plants contains about 13% sulfur by mass. When the oil bums, die sulfur forms sulfur dioxide gas ... 

Sulfur forms two oxides, SO2 (a gas at normal conditions) and S03 (a liquid that boils at 44.8°C). Under suitable conditions, S02 reacts with oxygen to form S03 ... 

Oxygen and sulfur occur naturally in the elemental state sulfur forms chains... 

Sulfur forms several oxides that in atmospheric chemistry are referred to collectively as SOx (read sox ). The most important oxides and oxoacids of sulfur are the dioxide and trioxide and the corresponding sulfurous and sulfuric acids. Sulfur burns in air to form sulfur dioxide, S02 (11), a colorless, choking, poisonous gas (recall Fig. C.1). About 7 X 1010 kg of sulfur dioxide is produced annually from the decomposition of vegetation and from volcanic emissions. In addition, approximately 1 X 1011 kg of naturally occurring hydrogen sulfide is oxidized each year to the dioxide by atmospheric oxygen ... 

Structures for many sulfides that do not occur as minerals have been reported in which sulfur forms four bonds directed to one side, leaving room for the unshared pair of the sulfur atom. There is little doubt that these sulfides, too, have transargononic structures, as suggested by Franzen (1966). 

C09-0136. Sulfur forms neutral compounds with oxygen, fluorine, and chlorine that display a variety of steric... 

Under normal conditions, sulfur forms yellow crystals. The ciystals consist of individual Sg molecules, with the eight sulfur atoms of each molecule arranged in a puckered ring. 

The generation of H2 from H2S by visible light has also been suggested . The efficiency of this process is increased by the presence of sulfite. The latter removes the sulfur formed in the oxidation of HjS to yield thiosulfate. Substitution of RUO2 by RuS2 leads to an increased H2 yield H2 from H2S is also formed in vanadium sulfide dispersions loaded with RUO2 ... 

The sulfur formed as a result of the last reaction is oxidized by bacteria in the following manner ... 

Am. In each ease, the answer is BuS. Part (ft) gives the ions and their charges, and so is perhaps easiest to answer. Part (know that periodic group IIA elements always form 2-t- ions in all their compounds and that sulfur forms a 2- ion in its compounds with metals. It is also necessary to remember that the metal is named first. In part (< ). the fact that there is only one compound of these two elements is deduced by the fact that the barium is stated with no Roman numeral, and that sulfide is a specific ion with a specific (2-) charge. 

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