Solids: Introduction
Overview
The information in the following table gives an overview of the relationships between the structure type, repetitive units (motifs), bonding forces, and properties of different solids.
- Tab.1
- Summary
Structure type | Repetitive units (motifs) | Lattice forces | Typical properties | Examples | |
---|---|---|---|---|---|
Atomic crystal | Three-dimensional structure | Atoms | Covalent bonds in three dimensions | High melting point Very hard Electrical insulators | Diamond, C (Abb. 1) , Silicon carbide, SiC, |
Atomic crystal | Layered structure | Atoms | Covalent bonds in two dimensions, London interactions | High melting point Soft Flaky | Graphite, C (Abb. 2) , Cadmium iodide, CdI2, Molybdenum disulfide MoS2 |
Atomic crystal/Ionic crystal | Layered structure | Atoms and Ions | Covalent bonds in one dimension, Coulomb interactions | High melting point Soft Electrical insulator | Phyllosilicates, e.g.: Mica (Abb. 3) , Kaolinite, Al4[(OH)8|Si4O10], (Ton) |
Atomic crystal | Chain structure | Atoms | Covalent bonds in two dimensions, London interactions | Partially meltable Fibrous | Selenium, Se (Abb. 4) , Silicon disulfide, SiS2 |
Atomic crystal/ionic crystal | Chain structure | Atoms and Ions | Covalent bonds in one dimension, Coulomb interactions | Fibrous Electrical insulator | Asbestos (Abb. 5) , Molybdenum disulfide, MoS2 |
Ionic crystal | Three-dimensional structure | Ions | Electrostatic interactions | High melting point Hard, brittle Electrical insulator | Sodium chloride, NaCl, (table salt) (Abb. 6) , Potassium chloride, KCl, Potassium nitrate, KNO3 |
Molecular crystal | Three-dimensional structure | Polar molecules | London and dipole-dipole interactions | Low melting point Soft Electrical insulator | Ice, H2O (Abb. 7) , Ammonia, NH3 |
Molecular crystal | Three-dimensional structure | Nonpolar molecules | London interactions | Low melting point Soft Electrical insulator | Carbon dioxide, CO2 (Abb. 8) , Hydrogen, H2, Methane, CH4 |
Molecular crystal | Three-dimensional structure | Positive ions Mobile electrons | Metallic bonds | Often high melting point Ductile Electrical conductor | Copper, Cu,Gold, Au, Iron, Fe, Potassium, K (Abb. 9) , |
Figures
- Fig.1
- Diamond
- Fig.2
- Graphite
- Fig.3
- Mica