Inorganic compounds, oxidation

Chemoautotrophic Inorganic compound O, or another inorganic compound Oxidized inorganic compound... 

Chemoautotroph Oxidation of inorganic compounds Oxidation of inorganic compounds co2 Hydrogen, sulfur, iron, and denitrifying bacteria... 

All the examples above involved inorganic compounds oxidation and reduction reactions can also take place with organic compounds. For example, methane can be oxidized to carbon dioxide (CO ) (effectively the oxidation number of C changes from -4 to -f4). As mentioned in Chapter 4 primary alcohols can be oxidized to aldehydes... 

Reactions With Inorganic Compounds. In an investigation of the reactions of BrF with oxides (71—73), Httle or no reaction was found with the oxides of Be, Mg, Ce, Ca, Fe, Zn, Zr, Cd, Sn, Hg, Th, and the rare earths, whereas the oxides of Mo and Re formed stable oxyfluorides. 

Oxidation. Hydrogen peroxide is a strong oxidant. Most of its uses and those of its derivatives depend on this property. Hydrogen peroxide oxidizes a wide variety of organic and inorganic compounds, ranging from iodide ions to the various color bodies of unknown stmcture in ceUulosic fibers. The rate of these reactions may be quite slow or so fast that the reaction occurs on a reactive shock wave. The mechanisms of these reactions are varied and dependent on the reductive substrate, the reaction environment, and catalysis. Specific reactions are discussed in a number of general and other references (4,5,32—35). 

Chlorine and Bromine Oxidizing Compounds. The organo chlorine compounds shown in Table 6 share chemistry with inorganic compounds, such as chlorine/77< 2-3 (9-j5y and sodium hypochlorite/7 )< /-j5 2-5 7. The fundamental action of chlorine compounds involves hydrolysis to hypochlorous acid (see Cm ORiNE oxygen acids and salts). 

Tetravalent lead is obtained when the metal is subjected to strong oxidizing action, such as in the electrolytic oxidation of lead anodes to lead dioxide, Pb02 when bivalent lead compounds are subjected to powerful oxidizing conditions, as in the calcination of lead monoxide to lead tetroxide, Pb O or by wet oxidation of bivalent lead ions to lead dioxide by chlorine water. The inorganic compounds of tetravalent lead are relatively unstable eg, in the presence of water they hydrolyze to give lead dioxide. 

In addition to the materials shown in Table 1, other organic materials find a minor portion of their use in mbber processing, such as waxes and fatty acids. Also, the mbber industry uses modest amounts of inorganic compounds, notably elemental sulfur, zinc oxide, magnesium oxide, and sodium bicarbonate. 

Inorganic Compounds. Inorganic selenium compounds are similar to those of sulfur and tellurium. The most important inorganic compounds are the selenides, haUdes, oxides, and oxyacids. Selenium oxidation states are —2, 0, +1, +2, +4, and +6. Detailed descriptions of the compounds, techniques, and methods of preparation, and references to original work are available (1—3,5,6—10, 51—54). Some important physical properties of inorganic selenium compounds are Hsted in Table 3. 

Tellurium forms inorganic compounds very similar to those of sulfur and selenium. The most important teUurium compounds are the teUurides, haUdes, oxides, and oxyacids (5). Techniques and methods of preparation are given in the Uterature (51,52). The chemical relations of teUurium compounds are iUustrated in Figure 2 (53). 

Of the large volume of tin compounds reported in the Hterature, possibly only ca 100 are commercially important. The most commercially significant inorganic compounds include stannic chloride, stannic oxide, potassium staimate, sodium staimate, staimous chloride, stannous fluoride, stannous fluoroborate, stannous oxide, stannous pyrophosphate, stannous sulfate, stannous 2-ethyUiexanoate, and stannous oxalate. Also important are organotins of the dimethyl tin, dibutyltin, tributyltin, dioctyltin, triphenyl tin, and tricyclohexyltin families. 

It is pmdent to perform zone melting in a dry inert atmosphere. Oxygen causes most organic melts to oxidize slowly. Oxygen and moisture not only oxidize metals and semiconductors, but often enhance sticking to the container. Molten salts attack sUica more rapidly in the presence of moisture. Oxygen and water are considered impurities in some inorganic compounds. 

Exempt colorants are made up of a wide variety of organic and inorganic compounds representing the animal, vegetable, and mineral kingdoms. Some, like -carotene and 2inc oxide, are essentially pure factory-produced chemicals of definite and known composition. Others, including annatto extract, cochineal extract, caramel, and beet powder are mixtures obtained from natural sources and have somewhat indefinite compositions. 

The values given in the following table for the heats and free energies of formation of inorganic compounds are derived from a) Bichowsky and Rossini, Thermochemistry of the Chemical Substances, Reinhold, New York, 1936 (h) Latimer, Oxidation States of the Elements and Their Potentials in Aqueous Solution, Prentice-Hall, New York, 1938 (c) the tables of the American Petroleum Institute Research Project 44 at the National Bureau of Standards and (d) the tables of Selected Values of Chemical Thermodynamic Properties of the National Bureau of Standards. The reader is referred to the preceding books and tables for additional details as to methods of calculation, standard states, and so on. 

Other methods for indicating or implying the presence of an atom in a nonstandard valence state have been used, especially the use of the prefix hydro e.g. 108). Such methods are sometimes convenient for simple molecules, but they are difficult to apply generally. A more general method that has seen extensive use utilizes the italicized symbol for the element with a superscript Roman numeral to indicate the valence (e.g. 109). This method has been objected to, however, because of ambiguity the superscript Roman number is also used to indicate oxidation number in inorganic compounds, and italicized atomic symbols are customarily used as locants for substituents. The A convention is a modification of the principle of this method, and avoids the objection. It was made a Provisional Recommendation of lUPAC in 1981. 

Heteropolyacids (HPA) are the unique class of inorganic complexes. They are widely used in different areas of science in biochemistry for the precipitation of albumens and alkaloids, in medicine as anticarcinogenic agents, in industry as catalysts. HPA are well known analytical reagents for determination of phosphoms, silica and arsenic, nitrogen-containing organic compounds, oxidants and reductants in solution etc. 

While most of the earlier research was done on metals and alloys, more recently a good deal of emphasis has been placed on ceramics and other inorganic compounds, especially functional materials used for their electrical, magnetic or optical properties. A very recent collection of papers on oxides (Boulesteix 1998) illustrates this shift neatly. In the world of polymers, the concepts of phase transformations or phase equilibria do not play such a major role 1 return to this in Chapter 8. 

Staeking faults and sometimes proper polytypism are found in many inorganic compounds - to pick out just a few, zinc sulphide, zinc oxide, beryllium oxide. Interest in these faults arises from the present-day focus on electron theory of phase stability, and on eomputer simulation of lattice faults of all kinds investigators are attempting to relate staeking-fault concentration on various measurable character-isties of the compounds in question, such as ionicity , and thereby to cast light on the eleetronic strueture and phase stability of the two rival structures that give rise to the faults. 

Autotrophy A unique form of metabolism foimd only in bacteria. Inorganic compounds (e.g., NH3, N02-, S2, and Fe2+) are oxidized directly (without using sunlight) to yield energy. This metabolic mode also requires energy for C02 reduction, like photosynthesis, but no lipid-mediated processes are involved. This metabolic mode has also been called chemotrophy, chemoautotrophy, or chemolithotrophy. 

COD Chemical oxygen demand - the amount of oxygen in mg/1 required to oxidize both organic and oxidizable inorganic compounds. 

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