Oxidation Numbers in Inorganic Nomenclature

In Chap. 6 we placed Roman numerals at the ends of names of metals to distinguish the charges on monatomic cations. It is really the oxidation number that is in parentheses. This nomenclature system is called the Stock system. For monatomic ions, the oxidation number is equal to the charge. For other cations, again the oxidation number is used in the name. For example, Hg2 + is named mercury(I) ion. Its charge is 24- the oxidation number of each atom is 4-1. Oxidation numbers are also used for other cations, such as dioxovanadium(V) ion, V02 . The prefix 0x0- stands for oxygen. Oxidation numbers can be used with nonmetal-nonmetal compounds, as in sulfur(VI) oxide for SO3, but the older system using prefixes (Table 6-2) is still used more often. 

EXAMPLE 14.13. Name the following according to the Stock system (a) NiCh, (b) UO2SO4, and (c) P2O5. 

(a) Nickel(II) chloride (b) dioxouranium(VI) sulfate (c) phosphorus(V) oxide 

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Recognizing the empirical nature of oxidation numbers in inorganic chemistry nomenclature, and ending the use of this antiquated concept. 

There is no use of, no less dependence on, the admittedly empirical [87] concept of "oxidation number", as is the practice in IUPAC s inorganic nomenclature. 

The concept of oxidation number is interwoven into the fabric of inorganic chemistry in many ways, including nomenclature."... 

As in the nomenclature of other inorganic compounds, specific rules are followed for naming coordination compounds. In general, the number and type of ligands attached to the metal ion are specified, as is the oxidation state of the metal ion. 

The nomenclature of inorganic chemistry is based upon the assignment of numbers (positive or negative) to the atoms of the elements. These numbers, called oxidation numbers, are defined in the following way. 

The concept of oxidation number is used in the modern chemical naming of ionic inorganic substances. This system of nomenclature, or naming, is called the Stock notation. In this system the oxidation number is inserted immediately after the name of an ion. Roman numerals are inserted after the name or symbol of the element. For example ... 

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