chapter 13 the chemistry of solids. types of solids metals network ionic molecular amorphous
TRANSCRIPT
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 CO2, CI4• Amorphous glass, polyethylene
Chapter 13 The Chemistry of Solids
Types of Solids Characteristics
• Metals Copper - malleable• Network Quartz – non-malleable • Molecular CO2, CI4 – low melting pt
• Ionic & muscovite– cleaves easy Network, Layered structure
Table 13.1 Study this!
The Chemistry of Solids
What characteristic do these solids share?
The Chemistry of Solids
What characteristic do these solids share?
Repeating Structural Patternother terms:LatticeArrayCrystal Structure orCrystal 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.
Is this a good unit cell?
YES! This Unit Cell generates entire pattern by translation ONLY
Is this 2nd cell a good unit cell?
Is this 2nd cell a good unit cell?Yes! It also generates the pattern by translation.
2nd cell is larger: contains 2 white fishes
1st cell is smaller: contains 1 white fish
2nd cell is centered: contains 2 white fishes
1st & 3rd cell primitive: contains 1 white fish
m
m
m
m
One C4 and 2 types of mirrors = 4m
Asymmetric Unit = smallest piece
that generates entire unit cell
Cubic Unit Cells(highest symmetry)
Tetragonal Cells
Triclinic cells Monoclinic cells (lowest symmetry)
OrthorhombicCells
Hexagonal Cells
Cubic Unit Cells havea = b = c
= 90 deg
a
cb
Three Types of Cubic Unit Cells
a
cb
Simple Cubic Body Centered Cubic
Face CenteredCubic
These Three Cubic Unit Cells are Structuresof most Metallic Elements(also hexagonal, hcp, to be seen Friday)
Cu, Ag, Au are all fccCr, Mo, W are all bccOnly Po is simple cubic (rare— why?)
Simple Cubic Body Centered Cubic
Face CenteredCubic
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
Primitive cell
Asymmetric unit = smallest portion needed to create unit cell
2 Asym./cells
