Writing and Naming Binary
Molecular Compounds
• Composed of two anions (binary)
• Check on periodic table to make sure!
• Name describes the type and number of the
atoms in a molecule of the compound.
• The most metallic (farthest left element or
lowest) is written 1st.
• Write the second element changing the ending
to -ide.
• Be sure to place Greek prefixes before each
element to indicate the actual number of atoms
in the molecule. Never simplify!
• Note: Never place “mono” on the first element
Greek prefixes
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1- mono
2- di
3- tri
4- tetra
5- penta
6- hexa
7- hepta
8- octa
9- nona
10- deca
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CO
carbon monoxide
CO2
carbon dioxide
N 2O 5
dinitrogen pentoxide
SF3
sulfur trifluoride
Molecular Names to Formulas
• Disulfur heptachloride
• Xenon trioxide
• Dinitrogen tetroxide
• Sulfur hexachloride
• Carbon disulfide
• Oxygen difluoride