Oxides and oxoacids of sulfur

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 ... 

Oxides and Oxoacids of Sulfur Sulfur dioxide (S02) and sulfur trioxide (S03) are the most important of the various oxides of sulfur. Sulfur dioxide, a colorless,... 

Structure and bonding in oxides and oxoacids of carbon, sulfur, nitrogen, phosphorus, and chlorine... 

Reactions with sulfides, polysulfides, sulfur oxides and the oxoacids of sulfur are complex and the products depend markedly on reaction conditions (see also p. 745 for blue crystals in chamber acid). Some examples are ... 

Further, there is little difference in energy between the various oxidation state species of sulfur, a fact that is doubtless involved in the complicated oxoacid and oxoanion chemistry of sulfur. We have already discussed some aspects of the aqueous solution chemistry of the group 16 elements ... 

Discuss key features of Group 6A(16) compare the patterns in oxidation state, oxide acidity, and hydride and halide structures with those of Group 5A(15) and describe the sulfur oxides and oxoacids ( 14.7) (EPs 14.59-14.67)... 

Sulfur Oxides and Oxoacids Sulfur dioxide, SO2, is a colorless, toxic gas with a characteristic suffocating odor. Its presence in polluted air (from the burning of fossil fuels) is known to cause respiratory ailments. The SO2 molecule has a bent geometry with a bond angle of 119.5°, very close to that predicted by the VSEPR model (Figure 22.45). 

The chemistry of phosphorus and the heavier congeners is dominated by element to element (E-E) single bonds and, particularly in the case of phosphorus, the availability of l>d orbitals to form dir—pir double bonds with a variety of other atoms such as oxygen, nitrogen, and even sulfur. Orbital participation results in expanded octets as found in compounds such as PF5, SbCl5, X3P=0 (where X=F, Cl, Br, I), the phosphorus oxoadds and oxoanions, and a class of compounds called the phosphazenes. We will take up many of these cases as we encounter them in the appropriate sections under our usual survey of the hydrides, oxides and oxoacids, and halides. For now, however, let s take a quick look at the phosphazenes, formerly called the phosphonitriles, that contain both N and P atoms in the same molecule. 

Structures of selected sulfur and selenium oxides and oxoacids. (o) the molecular structure of sulfur dioxide,... 

These trends are general ones, observed with other oxoacids of the nonmetals. Recall, for example, that nitric acid, HNO3 (oxid. no. N = +5), is a strong acid, completely ionized in water. In contrast, nitrous acid, HNO2 (oxid. no. N = +3),isaweakacid(JCa = 6.0 X lO"" ). The electronegativity effect shows up with the strengths of the oxoacids of sulfur and selenium ... 

Commonly used oxidants in redox polymerization include peroxides, cerium(IV) salts, sodium hypochloride, persulfates, peroxydiphophate, and permanganate. Reducing agents are, for example, the salts of metals like Fe, Cr, Ce, Tf Co, Cu, oxoacids of sulfur, hydroxyacids,... 

The ricji oxoacid chemistry of sulfur (pp. 705-21) is not paralleled by the heavier elements of the group. The redox relationships have already been summarized (p. 755). Apart from the dark-brown hydrated monoxide Po(OH)2 , which precipitates when alkali is added to a freshly prepared solution of Po(ll), only compounds in the +4 and +6 oxidation states are known. 

In the literature, there are reports of work concerned with the measurement of oxoacidic properties of ionic melts by gravimetric measurements of the solubility of acidic gases in these media [76, 77], The solubility of sulfur(VI) oxide in molten sodium phosphates was determined by the gravimetric method [76], A correlation was obtained between the melt basicities and the solubility of gaseous acid S03 in them. Iwamoto reported the estimation of the basic properties of molten salt by measurements of acidic gas solubilities (carbon dioxide and water) in them [77], However, similar methods cannot be used widely, owing to two factors. The first of these consists in the fact that the solubility of any gas in a liquid phase obeys Henry s law. Let us consider the following system of reactions ... 

When a nonmetal oxide reacts with water, it forms an oxoacid with the same oxidation number as the nonmetal. Give the name and formula of the oxide used to prepare each of these oxoacids (a) hypochlorous acid (b) chlorous acid (c) chloric acid (d) perchloric acid (e) sulfuric acid (f) sulfurous acid (g) nitric acid (h) nitrous acid (i) carbonic acid (j) phosphoric acid. 

Like phosphorus, sulfur forms two common oxides and two oxoacids, one of which is essential to a wide variety of industries. 

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