Ternary ionic compounds naming

The first thing to point out is the charge on tin. While tin has more than one possible charge, you know it has to be two in this case because of the Roman numeral (II) that appears in the name. The formula Sn202 does not represent the smallest ratio of ions. You should notice that if each one of these subscripts is reduced by the new formula will be SnO. You can only reduce these subscripts if all subscripts in a formula can be reduced by the same amount (this will be more critical with ternary ionic compounds). 

When the ternary ionic compound that we are trying to name contains a cation (positive ion) with multiple oxidation states, we still need to employ the stock system. For example, if we were asked to name the compound with the formula Cu(N03)2, we would determine that the oxidation number of the copper must be +2, because there are two nitrate ions, each with a charge of -1, and +2 + 2(-l) = 0. This would give us the name copper (II) nitrate for this compound. 

Many ionic compounds, such as NaCl, KBr, Znlj, and AI2O3, are binary compounds, that is, compounds formed from just two elements. For binary compounds, the first element named is the metal cation, followed by the nonmetallic anion. Thus, NaCl is sodium chloride. We name the anion by taking the first part of the element name (the chlor- of chlorine) and adding -ide. The names of KBr, Znh, and AI2O3 are potassium bromide, zinc iodide, and aluminum oxide, respectively. The -ide ending is also used in the names of some simple polyatomic anions, such as hydroxide (OH ) and cyanide (CN ). Thus, the compounds LiOH and KCN are named Uthium hydroxide and potassium cyanide, respectively. These and a number of other such ionic substances are ternary compounds, meaning compounds consisting of three elements. Table 0.3 lists the names of some common cations and anions. 

What about covalent compounds Covalent compounds are nonicmic, molecular compounds. For the most part, they contain only nonmetal atoms. A huge number of such compounds exist, and the naming schemes for these are much more involved than what we have seen for ionic compounds. The schemes we will study in this chapter are limited to compounds that contain only two nonmetals and compounds that are acids. Compounds, whether ionic or covalent, that contain just two elements are called binary compounds. Compounds, whether ionic or covalent, that contain three elements are called ternary compounds. The naming scheme for binary covalent compounds is discussed in Section 3.7. The naming scheme for acids, both binary and ternary, is discussed in Section 3.8. 

The -ide ending is also used for certain anion groups containing different elements, snch as hydroxide (OH ) and cyanide (CN ). Thus the compounds LiOH and KCN are named lithium hydroxide and potassium cyanide, respectively. These and a nnmber of other such ionic substances are called ternary compounds, meaning compounds consisting of three elements. Table 2.3 lists alphabetically the names of a number of common cations and anions. 

The majority of acids are ternary compounds. They contain three different elements—hydrogen and two other nonmetals. If one of the nonmetals is oxygen, the acid is called an oxoacid. Think of oxoacids as combinations of hydrogen ions (H ) and oxoanions. The scheme for naming oxoacids is similar to that outlined for oxoanions, except that the ending -ous is used instead of -ite and -ic instead of -ate. Several oxoacids are listed in Table 3.6. Also listed are the names and formulas of compounds in which the hydrogen of the oxoacid has been replaced by a metal, such as sodium. These compounds are called salts we will say much more about them in later chapters, beginning in Chapter 5. Acids are molecular compounds, and salts are ionic compoimds. 

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