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Unit 1
Elements of Chemical Structure and Inorganic Nomenclature

1-7. NUMBER PREFIXES

We often use prefixes to denote the number of atoms of an element in a compound. For example, CO contains one oxygen atom and is named carbon monoxide. Mon or mono indicates one atom. Here is a list of the commonly used number prefixes:

 

Examples

Mono, mo = one CO Carbon monoxide
Di = two CO2 Carbon dioxide
Tri = three SO3 Sulfur trioxide
Tetra  = four CF4 Carbon tetrafluoride
Penta  = five    
Hexa = six    
Hepta = seven    
Octa = eight    
Nona  = nine    
Deca = ten