Lesson 10

(7) Network or Molecular Compounds

Obj. 7.  From the name of a compound, determine whether it is network or molecular.

Again, the guideline for this is dependent on what kind of bonding you have. In a compound, you will either have ionic bonding or covalent bonding. If you have ionic bonding, you will be dealing with a network material. On the other hand, if you have covalent bonding, you will probably have a molecular material. The exceptions, again, are boron, carbon (in the form of graphite and diamond), silicon and silicon dioxide. The only one of these exceptions that is a compound is the silicon dioxide. So if you have silicon dioxide, which is also called quartz, then that would be a network covalent material. Other covalent materials (at least the ones we deal with in this course) will be molecular.

Exercises

Which of the following compounds are network materials and which are molecular materials?

a. carbon dioxide
b. silicon dioxide
c. nitrogen dioxide
d. sodium chloride
e. hydrogen sulfide
f. ferrous bromide
g. water

Worked-Out Examples (f,g)

(f) Ferrous bromide contains iron and bromine, a metal and a nonmetal, so it would have ionic bonding and therefore it would be a network material.

(g) Water contains hydrogen and oxygen, both nonmetals, therefore it has covalent bonding. It is not one of the exceptions that happens to be network covalent, therefore, it will be a molecular covalent material.

Answers to Exercises

Which of the following compounds are network materials and which are molecular materials?

a. carbon dioxide - molecular
b. silicon dioxide - network
c. nitrogen dioxide - molecular
d. sodium chloride - network
e. hydrogen sulfide - molecular
f. ferrous bromide - network
g. water - molecular

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