Binary compounds of nonmetals

The first compounds to be discussed will be compounds of two nonmetals. These binary compounds are named with the element to the left or below in the periodic table named first. The other element is then named, with its ending changed to -ide and a prefix added to denote the number of atoms of that element present. If there is more than one atom of die first element present, a prefix is used with the first element also. If one of the elements is to the left and the other below, the one to the left is named first unless that element is oxygen or duorine, in which case it is named last. The same order of elements is used in writing formulas for these compounds. (The element with the lower electronegativity is usually named first refer to Table 5-1.) The predxes are presented in Table 6-2. The first six prefixes are the most important to memorize. 

Number of Atoms Prefix Number of Atoms Prefix 

1 mono (or mon before names starting with a or 0) 2 di 3 tri 4 tetra (or tetr before names starting with a or 0) 5 penta (or pent before names starting with a or 0) 6 hexa 7 hepta 8 octa 9 nona 10 deca 

The systematic names presented for binary nonmetal-nonmetal compounds are not used for the hydrogen compounds of group III, TV, and V elements or for water. These compounds have common names which are used instead. Water and ammonia (NH3) are the most important compounds in this class. See Sec. 6.4 for acid names. 

EXAMPLE 6.1. Name and write the formula for a compound containing two atoms of oxygen and one atom of sulfur in each molecule. 

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Binary compounds of nonmetals are named with a set of classical prefixes, not used for most other compounds. 

Using Figure 5.4, determine the formulas of two binary compounds of nonmetals that have only nonpolar bonds and thus only van der Waals forces and lack of total symmetry. 

Many of the best-known binary compounds of the nonmetals have acquired common names. These are widely—and in some cases exclusively—used. Examples include... 

In general, binary compounds of two nonmetals are molecular, whereas binary compounds formed by a metal and a nonmetal are ionic. Water (H20) is an example of a binary molecular compound, and sodium chloride (NaCl) is an example of a binary ionic compound. As we shall see, these two types of compounds have... 

Nitrogen trichloride. Although this is a binary compound of two nonmetals, it can be named with Roman numeral designations. It is indeed possible to call this nitrogen(III) chloride in the most modern usage, but most chemists do not do that yet. 

Binary compounds of two nonmetals are covalently bonded. However, strong acids in water form ions completely. 

Binary compounds of a metal and nonmetal are usually ionic. 

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. ... 

Selenides. Selenium forms compounds with most elements. Binary 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 alkali metals to sluggish and requiring high temperature with hydrogen. 

CH2=CH2 + H20 - CH3CH2OH. hydride A binary compound of a metal or metalloid with. hydrogen the term is often extended to include all binary compounds of hydrogen. A saline or saltlike hydride is a compound of hydrogen and a strongly electropositive metal a molecular hydride is a compound of hydrogen and a nonmetal a metallic hydride is a compound of certain d-block metals and hydrogen. 

The preceding sections discuss the preparation, properties, and uses of several typical nonmetals. You should recognize that these elements are capable of forming many binary, ternary, and complex compounds and that the task of becoming familiar with all these individual substances would be a formidable one. Because only a few of these compounds warrant consideration from the standpoint of their practical utility, the following sections are concerned with the study of the more important binary compounds of the elements treated. Other binary and ternary compounds of nonmetals are encountered. 

Although the general term carbide applies to the binary compounds of the element carbon, this term is used in systematic nomenclature only when carbon is the more electronegative of the two elements involved. Thus, C02 is called carbon dioxide and not oxygen carbide since oxygen is more electronegative than carbon. Although carbon forms binary compounds with most of the nonmetals, metalloids, and metals, only a few of the more common members of this class are considered here. 

At that date, palladium hydride was regarded as a special case. Lacher s approach was subsequently developed by the author (1946) (I) and by Rees (1954) (34) into attempts to frame a general theory of the nature and existence of solid compounds. The one model starts with the idea of the crystal of a binary compound, of perfect stoichiometric composition, but with intrinsic lattice disorder —e.g., of Frenkel type. As the stoichiometry adjusts itself to higher or lower partial pressures of one or other component, by incorporating cation vacancies or interstitial cations, the relevant feature is the interaction of point defects located on adjacent sites. These interactions contribute to the partition function of the crystal and set a maximum attainable concentration of each type of defect. Conjugate with the maximum concentration of, for example, cation vacancies, Nh 9 and fixed by the intrinsic lattice disorder, is a minimum concentration of interstitials, N. The difference, Nh — Ni, measures the nonstoichiometry at the nonmetal-rich phase limit. The metal-rich limit is similarly determined by the maximum attainable concentration of interstitials. With the maximum concentrations of defects, so defined, may be compared the intrinsic disorder in the stoichiometric crystals, and from the several energies concerned there can be specified the conditions under which the stoichiometric crystal lies outside the stability limits. 

I ILICON-CONTAINING CERAMICS include the oxide materials, silica and silicates the binary compounds of silicon with nonmetals, principally silicon carbide and silicon nitride silicon oxynitride and the sialons main group and transition metal silicides and, finally, elemental silicon itself. Throughout the world, research activity on the preparation of all of these classes of solid silicon compounds by newer preparative techniques is vigorous. 

The preceding method is sufficient for naming binary ionic compounds containing metals that exhibit only one oxidation number other than zero (Section 4-4). Most transition metals and the metals of Groups IIIA (except Al), IVA, and VA, exhibit more than one oxidation number. These metals may form two or more binary compounds with the same nonmetal. Ta distinguish among all the possibilities, the oxidation number of the metal is indicated by a Roman numeral in parentheses following its name. This method can be applied to any binary compound of a metal and a nonmetal. 

Hydrogen is a nonmetal. All binary compounds of hydrogen are covalent., except for certain metal hydrides such as NaH and CaH2y which contain hydride, H, ions. 

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