[orgo814]

Can anyone help me differentiate between network solids and molecular solids? I know what they are but how can I tell by looking at a molecule whether it's a network or molecular solid? Is it really just allotropes of carbon and silicon molecules which are network solids? Any help is appreciated, thank you.

[NathanielZhu]

Correct me if I'm wrong but aren't network solids simply ionic lattices and molecular solids formed from covalent bonds?
For example, a NaF lattice is a network solid because NaF is ionic, and a diamond is a molecular solid because it's merely a bunch of Carbon atoms bonded covalently.

[orgo814]

No, a network solid is an extensive network of covalent bonds.

[PIQgoogleme]

Molecular solid: think ice. There are covalent bonds present, but they're within a molecule, not between the molecules. What holds the molecule together are dispersion forces, dipole-dipole interactions or hydrogen bonds.

Covalent network solid: Think diamond. All of the carbon atoms in the entire substance are covalently bonded, forming a big network. Technically, a diamond is like one big molecule.

[XGen]

I know what they are but how can I tell by looking at a molecule whether it's a network or molecular solid?

If you are looking at a drawing of a molecule, it is very simple. A network solid is not composed of separate molecules, but rather it is one gigantic molecule. Therefore, there should be no set drawing of a "molecule" of a network solid.