Different types of structure solids

From lecture 1 of Solid states and Diffraction

What dictates the macroscopic properties of a material

The microscopic structure

What are the 4 main types of solid structures

-Molecular solids

-Covalent networks

-Metallic solids

-Ionic solids

Describe Molecular Solids

-Molecular solids, such as iodine where there are strong covalent bonds within molecules but weak intermolecular attractions between 

Describe Covalent Networks

-Covalent networks, such as silicone where each atom forms four covalent bonds with each other forming a lattice structure. 

Describe Metallic solids

-Metallic solids, such as iron these join metal cations with a sea of delocalised electrons too form a solid 

Describe Ionic Solids

-Ionic solids, such as sodium chloride where ions are held in a lattice by electrostatic attraction. 

Describe allotropes and use an example

-Allotropes, are different structural forms of the same element. For example carbon forms allotropes of diamond, graphite, and buckminsterfullerene. 

-Diamond is hard, insulating, abrasive. In giant covalent network forming lattice structure. 

-Graphite is soft, conducting, and lubricating. Forms covalent network of layers of carbon. 

Describe what a polymorph is, use a brief example

-Polymorphs, are different crystal structures of the same compound. For example SiO4 forms both quartz and B-cristobalite.