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Chapter 13 The Chemistry of Solids. Chapter 13 The Chemistry of Solids. Types of Solids Metals Network Ionic Molecular Amorphous. Chapter 13 The Chemistry of Solids. Types of Solids Examples Metals Copper Network Quartz Ionic NaCl Molecular CO 2 , CI 4
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Chapter 13 The Chemistry of Solids • Types of Solids • Metals • Network • Ionic • Molecular • Amorphous
Chapter 13 The Chemistry of Solids • Types of SolidsExamples • MetalsCopper • NetworkQuartz • IonicNaCl • MolecularCO2, CI4 • Amorphousglass, polyethylene
Chapter 13 The Chemistry of Solids • Types of SolidsCharacteristics • MetalsCopper - malleable • NetworkQuartz – non-malleable • MolecularCO2, CI4 – low melting pt • Ionic &muscovite– cleaves easy • Network, • Layered structure
The Chemistry of Solids What characteristic do these solids share?
The Chemistry of Solids What characteristic do these solids share? Repeating Structural Pattern other terms: Lattice Array Crystal Structure or Crystal Lattice
The Chemistry of Solids What repeats? Simplest Repeating Pattern: • UNIT CELL is the smallest piece of the pattern that generates the lattice. • in 2 D — wallpaper or Escher • in 3 D — crystal structures
The Chemistry of Solids UNIT CELL is a conventional choice. May have several unit cells possible, Different in shape and/or size. Translation directions
The Chemistry of Solids UNIT CELL is a conventional choice. May have several unit cells possible, Different in shape and/or size.
YES! This Unit Cell generates entire pattern by translation ONLY
Is this 2nd cell a good unit cell?Yes! It also generates the pattern by translation.
1st cell is smaller: contains 1 white fish 2nd cell is larger: contains 2 white fishes
1st & 3rd cell primitive: contains 1 white fish 2nd cell is centered: contains 2 white fishes
m m m m One C4 and 2 types of mirrors = 4m
Asymmetric Unit = smallest piece that generates entire unit cell
Triclinic cells Monoclinic cells (lowest symmetry) Orthorhombic Cells Tetragonal Cells Cubic Unit Cells (highest symmetry) Hexagonal Cells
Cubic Unit Cells have a = b = c a = b = c = 90 deg c b a
Three Types of Cubic Unit Cells c b a Body Centered Cubic Face Centered Cubic Simple Cubic
These Three Cubic Unit Cells are Structures of most Metallic Elements (also hexagonal, hcp, to be seen Friday) Cu, Ag, Au are all fcc Cr, Mo, W are all bcc Only Po is simple cubic (rare— why?) Body Centered Cubic Face Centered Cubic Simple Cubic
What is one result of a metal’s “choice” to adopt a cubic, bcc or fcc lattice? Simple Cubic Body Centered Cubic Face Centered Cubic
Asymmetric unit = smallest portion needed to create unit cell 2 Asym./cells