Oxygen with nonmetals

Berzehus (19) further appHed and amplified the nomenclature introduced by Guyton de Morveau and Lavoisier. It was he who divided the elements into metalloids (nonmetals) and metals according to their electrochemical character, and the compounds of oxygen with positive elements (metals) into suboxides, oxides, and peroxides. His division of the acids according to degree of oxidation has been Httie altered. He introduced the terms anhydride and amphoteric and designated the chlorides in a manner similar to that used for the oxides. 

Metals react with nonmetals. These reactions are oxidation-reduction reactions. (See Chapters 4 and 18). Oxidation of the metal occurs in conjunction with reduction of the nonmetal. In most cases, only simple compounds will form. For example, oxygen, 02, reacts with nearly all metals to form oxides (compounds containing O2-). Exceptions are the reaction with sodium where sodium peroxide, Na202, forms and the reaction with potassium, rubidium, and cesium where the superoxides, K02, Rb02, and Cs02 form. 

Neptunium has an affinity for combining with nonmetals (as do all transuranic elements) such as oxygen, the halogens, sulfur, and carbon. 

As with most other transuranic elements of the actinide series, fermium has an oxidation state of +3, as well as possibly a +2 oxidation state. Thus, this ion can combine with nonmetals, such as oxygen and the halogens, as do many of the other elements in this series. Two examples follow ... 

Iron reacts with nonmetals forming their binary compounds. It combines readily with halogens. Reaction is vigorous with chlorine at moderate temperature. With oxygen, it readily forms iron oxides at moderate temperatures. In a finely divided state, the metal is pyrophoric. Iron combines partially with nitrogen only at elevated temperatures. It reacts with carbon, sulfur, phosphorus, arsenic, and silicon at elevated temperatures in the absence of air, forming their binary compounds. 

Oxygen difluoride reacts with nonmetals, such as sulfur and phosphorus, forming fluorides and oxyfluorides ... 

The chemical properties of selenium fall between sulfur and tellurium. Thus, selenium reacts with oxygen similarly to sulfur, forming two oxides, selenium dioxide, Se02 and trioxide, SeOs. The metal combines with halogens forming their halides. With nonmetals, selenium forms binary compounds exhibiting oxidation states +4 and -i-6. 

On the other hand, with nonmetals, such as hydrogen, carbon, sulfur, and phosphorus, oxygen forms covalent oxides ... 

Oxygen forms ionic oxides, such as Li20 and MgO, with active metals, and covalent oxides, such as P4OK) and SO3, with nonmetals. Oxides can also be classified according to their acid-base properties. Basic oxides are ionic, and acidic oxides are covalent. Amphoteric oxides, such as AI2O3, exhibit both acidic and basic properties. 

Fig. 27. RDFs for 1 M erbium(III) nitrate and chloride solutions in DMSO (solid lines) with nonmetal interactions eliminated. DMSO is coordinated over oxygen with an average Er—O—S angle of abut 130°. Nitrate is coordinated as a bidentate ligand. The Er—Cl distance for chloride in the first coordination sphere is 2.57 A. Theoretical values calculated for Er(N03)15(dmso)59 in the nitrate solution and ErCl13(dmso)5 2 in the chloride solution are marked by dots. The contributions from the coordinated anions (N03 or Cl ) are separately shown as dotted lines.

A1 is frequently used to obtain good barrier properties with polymer webs and, despite the very thin metal layers produced, the barrier of the metallized film to water vapor (WVTR) and oxygen (OTR) is markedly improved compared with nonmetal-lized film. This enhancement of the barrier is the reason aluminum metallized films are used in packaging. 

In Chap. 6 we placed Roman numerals at the ends of names of metals to distinguish the charges on monatomic cations. It is really the oxidation number that is in parentheses. This nomenclature system is called the Stock system. For monatomic ions, the oxidation number is equal to the charge. For other cations, again the oxidation number is used in the name. For example, Hg2 + is named mercury(I) ion. Its charge is 24- the oxidation number of each atom is 4-1. Oxidation numbers are also used for other cations, such as dioxovanadium(V) ion, V02". The prefix 0x0- stands for oxygen. Oxidation numbers can be used with nonmetal-nonmetal compounds, as in sulfur(VI) oxide for SO3, but the older system using prefixes (Table 6-2) is still used more often. 

The relative ease with which the alkali metals lose electrons to form M+ cations means that they react with nonmetals to form ionic compounds. Although we might expect the alkali metals to react with oxygen to form regular oxides of the general formula M20, lithium is the only one that does so in the presence of excess oxygen gas ... 

Uranium is a relatively reactive element. It combines with nonmetals such as oxygen, sulfur, chlorine, fluorine, phosphorus, and bromine. 

MgO]—Magnesium, an alkaline earth metal with two valence electrons, has an oxidation number of + 2. Oxygen, a nonmetal with six valence electrons, has an oxidation number of -2. They combine in a 1 1 ratio because +2 + -2 = 0. 

Nature of Chemical Bonds for Oxygen in its Compounds Table 3-4 Examples of Oxygen Covalent Bonding with Nonmetals... 

Like oxygen, sulfur gains two electrons and forms the sulfide ion (S ) when it reacts with metals or with hydrogen. But in its reactions with nonmetals, sulfur can have other oxidation numbers. Much of the sulfur produced in the United States is taken from deposits of elemental sulfur by the Frasch process, shown in Figure 8.8. 

Oxygen forms binary compounds with nearly all elements. Most may be obtained by direct reaction, although other methods (such as the thermal decomposition of carbonates or hydroxides) are sometimes more convenient (see Topic B6). Oxides may be broadly classified as molecular, polymeric or ionic (see Topics B1 and B2). Covalent oxides are formed with nonmetals, and may contain terminal (E=0) or bridging (E-O-E) oxygen. Especially strong double bonds are formed with C, N and S. Bridging is more common with heavier elements and leads to the formation of many polymeric structures such as Si02 (see Topics FT and F4). 

Polonium is a radioactive element that is difficult to study in the laboratory.) Oxygen has a tendency to accept two electrons to form the oxide ion (O ) in many ionic compounds. Sulfur, selenium, and tellurium also form dinegative anions (S, Se, and Te ). The elements in this group (especially oxygen) form a large number of molecular compounds with nonmetals. The important compounds of sulfur are SO2, SO3, and H2S. Sulfuric acid is formed when sulfur trioxide reacts with water ... 

Nonmetals share electrons with oxygen, so nonmetal oxides are covalent. In water, they act as acids, producing ions and reacting with bases. 

Most metals are found in nature in compounds with nonmetals such as oxygen and sulfur. For example, iron exists as iron ore (which contains Fe203 and other oxides of iron). 

Metals are very important for structural applications, electrical wires, cooking utensils, tools, decorative items, and many other purposes. However, because the main chemical characteristic of a metal is its ability to give up electrons, almost all metals in nature are found in ores, combined with nonmetals such as oxygen, sulfur, and the halogens. To recover and use these metals, we must separate them from their ores and reduce the metal ions. Then, because most metals are unsuitable for use in the pure state, we must form alloys that have the desired properties. The process of separating a metal from its ore and preparing it for use is known as metallurgy. The steps in this process are typically... 

Nonmetal ions As shown in Table 7.3, nonmetals gain the number of electrons that, when added to their valence electrons, equals 8. For example, consider phosphorus, with five valence electrons. To form a stable octet, the atom gains three electrons and forms a phosphide ion with a 3- charge. Likewise, oxygen, with six valence electrons, gains two electrons and forms a oxide ion with a 2- charge. 

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