With Nonmetal Compounds

Compounds with Group 3A Nonmetals Compounds with Group 4A Nonmetals Compounds with Group 5A Nonmetals Compounds with Group 6A Nonmetals Compounds with Group 7A Nonmetals... 

This naming system is used only with binary, nonmetal compounds, with one exception — Mn02 is commonly called manganese dioxide. 

Selenides. Selenium forms compounds with most elements. Biaary compounds of selenium with 58 metals and 8 nonmetals, and alloys with three other elements have been described (55). Most of the selenides can be prepared by a direct reaction. This reaction varies from very vigorous with alkah metals to sluggish and requiring high temperature with hydrogen. 

Interstitial Compounds. Tungsten forms hard, refractory, and chemically stable interstitial compounds with nonmetals, particularly C, N, B, and Si. These compounds are used in cutting tools, stmctural elements of kilns, gas turbines, jet engines, sandblast nozzles, protective coatings, etc (see also Refractories Refractory coatings). 

Table 2. Some Sulfide Compounds with Nonmetal—Metal Transitions...

Whereas finely divided cobalt is pyrophoric, the metal in massive form is not readily attacked by air or water or temperatures below approximately 300°C. Above 300°C, cobalt is oxidized by air. Cobalt combines readily with the halogens to form haUdes and with most of the other nonmetals when heated or in the molten state. Although it does not combine direcdy with nitrogen, cobalt decomposes ammonia at elevated temperatures to form a nitride, and reacts with carbon monoxide above 225°C to form the carbide C02C. Cobalt forms intermetallic compounds with many metals, such as Al, Cr, Mo,... 

When two nonmetals combine with each other, the product is most often a binary molecular compound. There is no simple way to deduce the formulas of such compounds. There is, however, a systematic way of naming molecular compounds that differs considerably from that used with ionic compounds. 

Elements at the right of the p block have characteristically high electron affinities they tend to gain electrons to complete closed shells. Except for the metalloids tellurium and polonium, the members of Groups 16/VI and 17/VII are nonmetals (Fig. 1.62). They typically form molecular compounds with one another. They react with metals to form the anions in ionic compounds, and hence many of the minerals that surround us, such as limestone and granite, contain anions formed from non-metals, such as S2-, CO,2-, and S042-. Much of the metals industry is concerned with the problem of extracting metals from their combinations with nonmetals. 

Hydrogen is unusual because it can form both a cation (1I+) and ail anion (11 ). Moreover, its intermediate electronegativity (2.2 on the Pauling scale) means that it can also form covalent bonds with all the nonmetals and metalloids. Because hydrogen forms compounds with so many elements (Table 14.2 also see Section 14.2), we shall meet more of its compounds when we study the other elements. 

The elements show increasing metallic character down the group (Table 14.6). Carbon has definite nonmetallic properties it forms covalent compounds with nonmetals and ionic compounds with metals. The oxides of carbon and silicon are acidic. Germanium is a typical metalloid in that it exhibits metallic or nonmetallic properties according to the other element present in the compound. Tin and, even more so, lead have definite metallic properties. However, even though tin is classified as a metal, it is not far from the metalloids in the periodic table, and it does have some amphoteric properties. For example, tin reacts with both hot concentrated hydrochloric acid and hot alkali ... 

In substitution reactions, hydrogen in its compounds with nonmetals often acts like a metal hence, it is listed among the metals in Table 7.1. 

In this chapter, we demonstrated that the restriction of building a compound with only one type of an element is not a restriction at all and a multitude of neutral, cationic as well as anionic polychalcogen structures is currently known. As expected for the more electronegative nonmetal (S) and meta metals (Se, Te), the bonding within these moieties is covalent and a small number of interactions, namely, p2-rap2 lone pair repulsion, n- and n -n bonding as well as p2- cr interactions, are sufficient to rationalize the structures and account for the bond lengths alternations or weak transannular interactions that are often found. 

If a nonmetal reacts with another nonmetal no electrons are lost or gained, but are shared. We call such compounds covalent (molecular) compounds. These compounds contain small units we call molecules. Ammonia, NH3, water, H20, and methane, CH4, are examples of covalent compounds. 

Finally, we need to consider compounds containing the nonmetal hydrogen. Remember that hydrogen is an exception. In simple binary compounds with nonmetals, we treat hydrogen as a metal. As a metal in the first column, it should have a +1 charge. Thus, H2S is hydrogen sulfide. 

Hydrogen is capable of forming compounds with all elements except the noble gases. In compounds with nonmetals, hydrogen usually behaves like a metal instead of a nonmetal. Therefore, when hydrogen combines with a nonmetal, it usually has a +1 oxidation number. When hydrogen combines with a metal, it usually has a —1 oxidation number. Hydrogen compounds with the transition metals are usually nonstoichiometric. Nonstoichiometric compounds have no definite formula. 

The periodic table can give us many clues as to the type of reaction that is taking place. One general rule, covered in more detail in the Bonding chapter, is that nonmetals react with other nonmetals to form covalent compounds, and that metals react with nonmetals to... 

The atmospheric oxygen that we breathe is a very reactive nonmetal and is colorless, odorless, and tasteless, but it is essential to all living organisms. It readily forms compounds with most other elements. With six electrons in its outer valence shell, it easily gains two more electrons to form a negative (—2) ion or as covalent, it can share electrons with other elements to complete its outer shell. 

Following are two examples of polonium s +2 and +4 oxidation states, in which the element mostly forms compounds with nonmetals. 

Their unique characteristics are a result of their outer shells having seven electrons, and thus requiring only one electron to become complete. This -1 oxidation state makes them extremely reactive with both metals and some nonmetal elements that form negative ions, and they may form either ionic or covalent bonds. They can also form compounds with each other these binary compounds of the halogens are called halides. ... 

Plutonium can form compounds with many nonmetals such as oxygen, the halogens, and nitrogen. It can also be used as an alloy with other metals. A few examples of plutonium compounds exhibiting the oxidation states of +3 and +4 follow ... 

Although little is known about mendelevium, it is possible to form compounds with some nonmetals such as oxygen and the halogen with its +3 ion, as follows ... 

Since nobelium has an oxidation state of +3, its ions are capable of forming compounds with a few nonmetals, as follows ... 

None now known. However, because seaborgium is a metal, it might be possible for it to form compounds with some nonmetals such as the halogens. 

Dysprosium combines with several nonmetals at high temperatures forming binary compounds with varying compositions. Heating with hydrogen produces dysprosium dihydride, DyH2, and dysprosium trihydride. DyH3. With sulfur, several sulfides have been synthesized that have the compositions... 

The metal reacts with halogens above 200°C forming its trihalides. It combines with nitrogen above 1,000°C producing a nitride, YN. It combines at elevated temperatures forming binary compounds with most nonmetals and some metalloid elements such as hydrogen, sulfur, carbon, phosphorus, silicon, and selenium. 

Q. Why do metals tend to form ionic compounds with nonmetals ... 

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