Polyatomic ions oxoanions

Polyatomic ions, as you have seen (Table 2.2), are given special names. Certain non-metals in Groups 15 to 17 of the periodic table form more than one polyatomic ion containing oxygen (oxoanions). The names of several such oxoanions are shown in Table 2.3. From the entries in the table, you should be able to deduce the following rules ... 

Some elements—particularly the halogens—form more than two kinds of oxoanions. The name of the oxoanion with the smallest number of oxygen atoms is formed by adding the prefix hypo- to the -ite form of the name, as in the hypochlorite ion, CIO-. The oxoanion with the most oxygen atoms is named with the prefix per- added to the -ate form of the name. An example is the perchlorate ion, C104-. The rules for naming polyatomic ions are summarized in Appendix 3A and common examples are listed in Table D.l. 

We first met polyatomic ions and oxoanions in Section C. Many of the most important and common polyatomic anions are the oxoanions (Table D.l). If only one oxoanion of an element is common, its name is formed by adding the suffix -ate to the stem of the name of the element, as in the carbonate ion, C032-. Some elements can form two types of... 

Polyatomic ions (as opposed to neutral molecules) may also be unstable with respect to decomposition, polymerisation or disproportionation. However, ions cannot be scrutinised in isolation. In a crystalline solid, there are always counter-ions of opposite charge to be considered, and in solution an ion is surrounded by solvent molecules. The intimacy of the chemical environment of any ion must influence its viability. For example, redox reactions involving electron transfer between cation and anion, or between ion and solvent, may find easy kinetic pathways. We look here at some examples of unstable oxoanions. 

An oxoacid is an acid formed from a polyatomic ion that contains oxygen, hydrogen, and another element. (Oxoacids are called oxyacids in some chemistry textbooks). In Chapter 3, you learned the names of common polyatomic ions and their valences (oxidation numbers). The names of oxoacids are similar to the names of their polyatomic oxoanions. Only the suffix is different. Study the three rules and examples for naming oxoacids below. Then try the Practice Problems that follow. 

Write the chemical formulas for the following acids. Then name and write the formulas for the oxoanions that form from each acid. Refer to Chapter 3, Table 3.5, Names and Valences of Some Common Polyatomic Ions, as necessary. 

Families of Oxoonions As Table 2.5 shows, most polyatomic ions are oxoan-ions, those in which an element, usually a nonmetal, is bonded to one or more oxygen atoms. There are several families of two or four oxoanions that differ only in the number of oxygen atoms. A simple naming convention is used with these ions. 

Polyatomic ions are those that contain more than one atom chemically bonded together. Oxoanions are polyatomic ions that contain one or... 

Most acids are oxoacids that is, they contain oxygen in addition to hydrogen and another element. When dissolved in water, an oxoacid yields one or more H+ ions and a polyatomic oxoanion, such as one of those listed in Table 2.4. 

Oxoanions are polyatomic anions that contain one or more oxygen atoms and one atom (the central atom ) of another element. Examples include the chlorate (ClOf), nitrate (NO J), and sulfate (SOl ) ions. Often, two or more oxoanions have the same central atom but different numbers of O atoms (e.g., NOJ and NO )-Starting witli the oxoanions whose names end in -ate, we can name these ions as follows ... 

---