Concept:Molecular crystals possess lattice points occupied by discrete molecules (like \( \text{I}_2 \), \( \text{S}_8 \), or \( \text{CO}_2 \)).
Solution:- Because the atoms within the molecules have already satisfied their bonding requirements via covalent bonds, the molecules themselves are entirely neutral.
- To hold these separate, neutral molecules together in a solid lattice, weak intermolecular forces must act between them.
- These overarching weak intermolecular forces (such as London dispersion forces or dipole-dipole interactions) are collectively termed Van Der Waals forces.
Why other options are incorrect:- A: Ionic bonds hold ionic crystals together.
- C: Covalent bonds hold the atoms inside the molecule together, not the molecules to each other (unless it's a giant covalent network like diamond).
- B: While hydrogen bonds are a specific, strong type of dipole-dipole interaction found in polar molecular crystals like ice, Van der Waals force is the broader, universally applicable answer for molecular crystals as a whole.
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