Naming Covalent/ Molecular Compounds

Covalent Bonds use Prefixes to indicate the number of atoms involved in the compounds

1= mono 6 = hexa

2 = di 7= hepta

3 = tri 8 = octa

4 = tetra 9 = nina

5 = penta 10 = deca

RULES

1- The name of the first element does not get changed, only a prefix is added if it is more than one.

Ex: Trisulfur tetrafluoride S3F4

2- The second element gets a different ending, as well as a prefix.

Ex : phosphorus trichloride PCl3(NOT: phosphorus trichlorine)

RULES continued..

3- If the first element in the compound is a single you do not write mono:

ex. CO2 - carbon dioxide (NOT monocarbon dioxide)

4- If the element’s name starts with a vowel, and the prefix ends with a vowel, you can drop the last vowel on the prefix:

ex. S5O10 - pentasulfur decoxide(NOT pentasulfur decaoxide)

RULES continued..

5- Covalent compounds do not get simplified. Name the compound exactly as you see it:

Ex. H2F2 = dihydrogen difluoride

(NOT hydrogen monofluoride HF)

TRY THESE:a) Diphosphorus pentoxideb) Nitrogen monoxidec) Xenon hexafluorided) Tetrarsenic decoxide

e) SiO2

f) N2S5

g)P4O10

h)BrCl6