IONIC SOLIDS, Schemes and Mind Maps of Chemistry

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Crystalline

Amorphous

Ionic Solids

Categories of solids

Categories of solids based on the particles that form the solid pack

1. Crystalline solids
2. Amorphous solids
3. Polycrystalline solids

Amorphous solids

• (literally, "solids without form") have a random structure.

Polycrystalline solids

• Aggregate of a large number of small crystals or grains in which the structure is regular, but the crystals or grains are arranged in a random fashion.

Molecular solids

• Intramolecular bonds between the atoms that form the molecules >>>
• intermolecular bonds between these molecules <<<
• Soft substances with low melting points.

Molecular solids

• Example: dry ice, or solid carbon dioxide
• The van der Waals forces holding the CO 2 molecules together are weak enough that dry ice sublimesit passes directly from the solid to the gas phase at -78oC.

Diamond

• Each carbon atom in diamond is covalently bound to four other carbon atoms oriented toward the corners of a tetrahedron
• Because all of the bonds in this structure are equally strong, covalent solids are often very hard and they are notoriously difficult to melt.

Ionic solids

• Held together by the strong force of attraction between ions of opposite charge.
• The strength of an ionic bond depends on the radii of the ions that form the solid.

Metallic solids

• Metal atoms don't have enough electrons to fill their valence shells by sharing electrons with their immediate neighbors.
• Electrons in the valence shell are therefore shared by many atoms, instead of just two.
• In effect, the valence electrons are delocalized over many metal atoms.

Metallic solids

• Because these electrons aren't tightly bound to individual atoms, they are free to migrate through the metal.
• As a result, metals are good conductors of electricity.
• Electrons that enter the metal at one edge can displace other electrons to give rise to a net flow of electrons through the metal.