Introduction to Naming Compounds
In Chemistry, the term Nomenclature refers to a set of rules used to name compounds formed by the reaction of two or more elements.
Other sciences also use the word nomenclature to systematically define terms and facts pertaning to specific disciplines.
Genarally speaking, the positive element (ion) is always written first and the negative element (ion) is written next to it.
In ionic compounds the general rule is the following
Cation + Anion = Neutral Compound
- Cation name remains the same in the element and the compound
- Anion's name ending changes according to valence electrons (valences used in bonding)
- These are compunds that are made up of two elements
- Binary Compounds always end in "IDE"
A compound of the two elements Tin and Chlorine can take everal different formulas and names
One compound that can be formed is SnCl2
Normally we could call this compound tin chloride but we could be more specific and call it tin dichloride.
Dichloride - meaning two chlorines ("di" form the latin word meaning "two")
There could be another compound between Tin and Chlorine with the formula SnCl4. This compund is called tin tetrachloride. Tetra in latin means "four".
Other forms of naming compound are:
- Latin Form or Suffix Method
- not commonly used - here the name of cation changes as well as anion, a suffix is added after the cation:
- "ous" for the lower oxidation state
- "ic" for the higher oxidation state
SnCl2 --- Stannous chloride
SnCl4. --- Stannic Chloride
- Roman Numeral Method - The Stock System
The Roman numeral indicates the charge on the transition metal
SnCl2 --- Stannous chloride --- tin (II) chloride
SnCl4. --- Stannic Chloride --- tin (IV) chloride
Name the following compounds:
- SO2 is called sulfur dioxide
- SiI4 is called silicon tetraiodide
- SF6 is called sulfur hexafluoride
- CS2 is called carbon disulfide