zum Directory-modus

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 typeRepetitive units (motifs)Lattice forcesTypical propertiesExamples
Atomic crystalThree-dimensional structureAtomsCovalent bonds in three dimensions High melting point Very hard Electrical insulators Diamond, C (Abb. 1) , Silicon carbide, SiC,
Atomic crystalLayered structureAtoms 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 crystalLayered structureAtoms 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 crystalChain structureAtoms Covalent bonds in two dimensions, London interactions Partially meltable Fibrous Selenium, Se (Abb. 4) , Silicon disulfide, SiS2
Atomic crystal/ionic crystalChain structureAtoms and Ions Covalent bonds in one dimension, Coulomb interactions Fibrous Electrical insulator Asbestos (Abb. 5) , Molybdenum disulfide, MoS2
Ionic crystalThree-dimensional structureIonsElectrostatic interactions High melting point Hard, brittle Electrical insulator Sodium chloride, NaCl, (table salt) (Abb. 6) , Potassium chloride, KCl, Potassium nitrate, KNO3
Molecular crystalThree-dimensional structurePolar moleculesLondon and dipole-dipole interactions Low melting point Soft Electrical insulator Ice, H2O (Abb. 7) , Ammonia, NH3
Molecular crystalThree-dimensional structureNonpolar moleculesLondon interactions Low melting point Soft Electrical insulator Carbon dioxide, CO2 (Abb. 8) , Hydrogen, H2, Methane, CH4
Molecular crystalThree-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.4
Gray selenium
Fig.6
Sodium chloride
Fig.7
H2O: Ice (and water)
Fig.8
Carbon dioxide
Dollar Bin
Fig.9
Potassium
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