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