Nomenclature ionic compounds

The aim of chemical nomenclature is to be simple but unambiguous. Ionic and molecular compounds use different procedures so it is important first to identify the type of compound. To name an ionic compound, we name the ions present and then combine the names of the ions. 

Table 6-1 Nomenclature Divisions for Inorganic Compounds Binary nonmetal-nonmetal compounds Ionic compounds...

Another point which needs to be clarified from the start is the nomenclature of metalated silanes We will frequently use the term silyl anion in this chapter when we talk about metalated silanes. Although the term anion defines, literally taken, an ionic compound, this expression, when used by us, does not necessarily imply that the compound in question is of ionic nature, but covers, as well, in analogy to the use of the term carbanion , silicon compounds with a polarized covalent silicon-metal bond. 

The word nomenclature simply means naming. You have already seen some chemical formulas such as NaCl, H20, and H2S04. There are many times when having names for chemicals is more convenient than having their formulas. Chemical naming falls into two main groups that for ionic compounds formed of positive and negative ions, and that for nonionic compounds. 

The nomenclature for molecular compounds is much less complicated than for ionic compounds. Molecular compounds are formed from covalently bonded nonmetallic elements. The formula for a molecule represents a stable unit of atoms, unlike a formula for an ionic compound, which only represents the simplest whole number ratio of ions. As a result, molecular formulas cannot be simplified like formulas for ionic compounds. An example would... 

Naming ionic compounds Chemical nomenclature is a systematic way of naming compounds. Now that you are famihar with writing chemical formulas, you will use the following general rules in naming ionic compounds when their formulas are known. 

Names of ionic compounds are derived from the names of their ions. The name of the cation appears first, followed by the name of the anion. In the Stock system for naming an ion (the systematic name), a Roman numeral indicates the charge of the cation. In the older common nomenclature system, the suffix -ous indicates the lower of the ionic charges, and the suffix -ic indicates the higher ionic charge. 

First we will use the nomenclature rules that we presented in Chapter 2 to write formulas for all of the compounds involved. Then we construct a balanced chemical equation using complete formula units. Next we must identify any ionic compounds that are present, and we write them as dissociated ions to give the total ionic equation. Finally, to obtain the net ionic equation, we must eliminate any spectator ions from both sides of the equation. 

The cations formed as shown by the half-reactions above are simply given the names of the metals that produced them, such as sodium for Na+ and calcium for Ca +. Since they consist of only one element, the name for each anion has an -ide ending, that is, hP", nitride CP , oxide S , sulfide H , hydride F, fluoride and Cl , chloride. An advantage in the nomenclature of ionic compounds is that it is not usually necessary to use prefixes to specify the numbers of each kind of ion in a formula unit. This is because the charges on the ions determine the relative numbers of each, as shown by the examples in Table 4.3. 

Except for those compounds in which the cation is H+ (adds) or the anion is OH (bases), the compounds that consist of a cation and an anion are salts. Therefore, the rules of nomenclature discussed for ionic compounds in Section 4.8 are those of salts. The salt product of Reaction 4.9.6, above, consists of K+ cation and Cl anion, so the salt is called potassium chloride. The salt product of Reaction 4.9.7, above, is made up of Ca + cation and S04 anion and is called calcium sulfate. The reaction product of LiOH base with H2SO4 add is composed of Li+ ions and SO42 ion. It takes 2 singly charged Li+ ions to compensate for the 2- charge of the S04 anion, so the formula of the salt is Li2S04. It is called simply lithium sulfate. It is not necessary to call it dilithium sulfate, because the charges on the ions denote the relative numbers of ions in the formula. 

Bases that contain hydroxide ion are named very simply by the rules of nomenclature for ionic compounds. The name consists of the name of the metal followed by hydroxide. For example, LiOH is lithium hydroxide, KOH is potassium hydroxide, and Mg(OH)2 is magnesium hydroxide. 

Some metal atoms, especially those of transition and inner-transition elements, form more than one type of charged ion. Copper, for example, forms both Cu and Cu, and iron forms Fe and Fe. The names of ionic compounds containing such elements must indicate which ion is present in the compound. A nomenclature system that does this well indicates the ionic charge of the metal ion by a roman numeral in parentheses following the name of the metal. Thus, CuCl is copper(l) chloride and CUCI2 is copper(ll) chloride. These names are expressed verbally as copper one chloride and copper two chloride. ... 

Many ionic compounds are binary confounds, or compounds formed from just two elements. For binary ionic compounds the first element named is the metal cation, followed by the nonmetallic anioa Thus, NaCl is sodium ehloride. The anion is named by taking the first part of the element name (ehlorine) and adding -ide. Potassium bromide (KBr), zinc iodide (Znl2), and aluminum oxide (AI2O3) are also binary compounds. Table 2.2 shows the -ide nomenclature of some eommon monatomic anions according to their positions in the periodic table. 

Chemical Nomenclature The names of simple ionic compounds, molecular compounds, and acids can all be written by examining their chemical formula. The nomenclature flowchart (Figure 5.16) shows the basic procedure for determining these names. Chemical Nomenclature Since there are so many compounds, we need a systematic way to name them. By learning these few simple rules, you will be able to name thousands of different compounds. The next time you look at the label on a consumer product, try to identify as many of the compounds as you can by examining their names. 

In this section, we discuss the nomenclature of some simple inorganic compounds. We hrst look at the naming of ionic compounds. Then, we look at the naming of some simple molecular compounds, including binary molecnlar componnds (molecular compounds of two elements) and acids. Finally, we look at hydrates of ionic compounds. These substances contain water molecules in loose association with ionic compounds. 

Chemical nomenclature is the systematic naming of compounds based on their formulas or structures. Rules are given for naming ionic compounds, binary molecular compounds, acids, and hydrates. 

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