Chapter 2 Bonding in Solids

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Chapter 2Bonding in Solids
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Types of bonding in solids

• Ionic bonding
• Covalent bonding
• van der Waals bonding
• Metallic bonding

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Ions and ionic radii
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Assignment of radii to ions is difficult
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The radius ratio rule(2rx)2 (2rx)2
2(rMrx)22rx?2 2 (rMrx) rM/rx 0.414
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Lattice energy of ionic crystals
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• Attractive energy
• Repulsive energy
• A Madelung constant

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Therefore,
when
then
and therefore
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Kapustinskiis equation
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The Born-Haber cycle

• Na(g) Cl-(g)? NaCl(s) , ?H U
• Na (s) 1/2 Cl 2(g)? NaCl(s) , ?H ?Hf
• Sublimation of solid Na ?H
  S
• Ionization of gaseous Na atoms ?H IP
• Dissociation of Cl2 molecules ?H
  1/2 D
• Formation of Cl- ion
  ?H EA
• Coalescence of gaseous ions to give crystalline
• NaCl
  ?H U

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Stabilities of real and hypothetical ionic
compounds
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Some examples
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d orbitals
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Octahedral complex and crystal field
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Tetrahedral and square planar
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Orientation of d orbitals in a tetrahedral field
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Crystal field splitting of energy level
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Jahn-Teller distortions
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Metallic bonding and band theory
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Free electron theory (Sommerfeld)
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Band structure of metals
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Overlapping band structure of Be
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Band structure of insulators
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Two types of conduction mechanism in
semiconductors

• Negative charge carriers (conduction band)
• Positive holes (valence band)

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Band structure of inorganic solids
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Transition metal compounds
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Fullerenes and graphite
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