Greek Prefixes are only used with Covalent or Polar Covalent compounds. Greek Prefixes are never used with Ionic Compounds.

The Greek Prefixes are as follows:

1  mono

2 di

3 tri

4 tetra

5 penta

6 hexa

7 hepta

8 octa

9 nona

10 deca

When using Greek Prefixes "mono" can never be used in the first element in the compound name.

For Example

NO2

Nitrogen dioxide is correct not mononitrogen dioxide.

N2O5

dintirogen pentaoxide

SO2

sulfur dioxide

XeF4

Xeon tetrafluoride