Nonmetallic oxides

Nonmetallic Oxidants lodobenzene Diacetate (IBD)-lmpregnated Alumina... 

IV. Nonmetallic Oxide + H20 —> Acid 1. Dinitrogen pentoxide is added to water ... 

Magnesium also reduces nonmetallic oxides, such as carbon dioxide, carbon monoxide, sulfur dioxide and nitrous oxide, burning at elevated temperatures. 

Let us now compare the internal oxidation of nonmetallic (oxide) solid solutions with the internal oxidation of metal alloys. The role of the (neutral) point defect... 

The change in the basic and acidic properties here shown for the oxides of main group elements which have the highest oxidation state number. The oxides in the blue colored regions are basic (metallic) oxides and the oxides in the red colored regions are acidic (nonmetallic) oxides. The oxides in both blue and red colored regions are amphoteric oxides (the oxides of amphoteric metals). 

N205 + H20 —> 2H+ + 2N03. Nonmetallic oxides are often called acid anhydrides. 

Fused salts (and mixtures of fused salts) are not the only type of liquid electrolytes. Mention has already been made of fused oxides and in particular mixtures of fused oxides. A typical fused oxide system is the result of intimately mixing a nonmetallic oxide (SiOj, GeOj, BjOj, P2OJ, etc.) and a metallic oxide (LijO, NajO, KjO, MgO, CaO, StO, BaO, AljOj, etc.) and then melting the mixture. The system can be represented by the general formula - R O, where M is the metallic element and R is the nomnetaUic element. 

Pure Fused Nonmetallic Oxides Form Network Structures Like Liquid Water... 

The type of solvent action that fused nonmetallic oxides have on metallic oxides may be likened to the second type of dissolution process, i.e., proton-transfer reactions. The process may be pictured as follows. The oxygens cannot discriminate between the metal ions (of the metallic oxide), with which they have been associated in the lattice of a metal oxide before dissolution, and the oxygen atoms of the Si04 tetrahedra contained in the solvent—fused silica. The oxygen atoms sometimes therefore leave the metal ions and associate with those of the tetrahedra. Dissolution has occurred with a type of oxygen-transfer reaction (see Fig. 5.69). 

There is a further analogy between the solvent actions exercised by water and a fused nonmetallic oxide. Just as water dissolves an electrolyte at the price of having its structure disturbed, so also the reaction resulting from the addition of a metallic oxide to a fused nonmetallic oxide like silica is equivalent to a bond mpture between the Si04 tetrahedra (Fig. 5.70). Solvent action occurs in fused oxide systems along with a certain breakdown of the network structures present in the pure liquid solvent (e.g., in pure liquid silica). 

In fused-oxide systems, a simple way of expressing the concentration of the metal oxide MjjOyin the fused nonmetallic oxide RpO is sometimes used. This involves the so-called 0/R ratio. The 0/R ratio is related to the mole fraction of the metallic... 

The broad approach used by Zachariasen in the network model of liquid silicates is to break down the network present in the pure fused nonmetallic oxide thus... 

The techniques listed below have been used primarily for synthesis of nonmetallic oxides, but in principle they should also be applicable to metallic oxides. 

Acidic anhydrides are nonmetallic oxides that react with water to form acids. Basic anhydrides are metallic oxides that react with water to form bases. 

Figure 15.8 shows the formulas of a number of oxides of the representative elements in their highest oxidation states. Note that all alkali metal oxides and all alkaline earth metal oxides except BeO are basic. Beryllium oxide and several metallic oxides in Groups 3A and 4A are amphoteric. Nonmetallic oxides in which the oxidation number of the representative element is high are acidic (for example, N2O5, SO3, and CI2O7), but those in which the oxidation number of the representative element is low (for example, CO and NO) show no measurable acidic properties. No nonmetallic oxides are known to have basic properties. 

In steelmaking, nonmetallic impurities such as P, S, and Si are removed as the corresponding oxides. The inside of the furnace is usually lined with CaC03 and MgC03, which decompose at high temperatures to yield CaO and MgO. How do CaO and MgO help in the removal of the nonmetallic oxides ... 

Nonmetallic oxides that intercalate graphite include NjOj, SO3, CI2O7 and SeOj, corresponding to anhydrides of inorganic acids The intercalation compounds of these anhydrides have much in common with those of graphite with inorganic acids, discussed in 16.4.2.1.4. 

---