The Stock System
History- The type of naming you will learn about is called the Stock system or Stock's system. It was designed by Alfred Stock (1876-1946), a German chemist and first published in 1919. In his own words, he considered the system to be "simple, clear, immediately intelligible, capable of the most general application."
In 1924, a German commission recommended Stock's system be adopted with some changes. For example, FeCl2,which would have been named iron(2)-chloride according to Stock's original idea, became iron(II) chloride in the revised proposal. In 1934, Stock approved of the Roman numerals, but felt it better to keep the hyphen and drop the parenthesis. This suggestion has not been followed, but the Stock system remains in use world-wide.
How do we name compounds when the cation of variable charge is involved?
Some elements have more then one oxidation number and when naming a compound these must be identified. Roman numerals are shown after the cation in parenthesis( ) to indicate the oxidation number.
To determine what the oxidation number is, you must use the anion (negative ion) to determine what the positive oxidation number is.
Below you can see some of the elements with more than 1 oxidation number.
Example- Pb(NO3)4 write the name "lead nitrate". Since lead has more than one oxidation state we must figure out which lead we have. Since each nitrate (4 of them) has a 1- charge, the Pb must be 4+. So our roman numeral will be (IV).
Pb(NO3)4 is named "lead(IV) nitrate"
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