Gases: Dimensionless particles in constant straight line motion colliding with their container walls 100 % elastically to create pressure

Liquids: Condensed state in which the particles are clustered (100-1000 particles). Order is found within the clusters but not from cluster to cluster. Attractive forces significant to make clusters but not significant enough to keep clusters from

moving past each other.

Solids:

Structural units

with attractive forces between the particles strong enough to make a rigid structure.(i.e. particles held in fixed positions by chemical bonds)

Solids: Structural units with attractive forces between the particles strong enough to make a rigid structure.With An Order Without An Order

(crystalline) (amorphous)

Scanning Tunneling Micrograph of the surface of Platinum

Scanning Tunneling Micrograph of the surface of graphite.

Solids: Structural units with attractive forces between the particles strong enough to make a rigid structure.

A polyhedron with six faces, all of which are parallelograms

With An Order Without An Order(crystalline) (amorphous)

Simplest Repeating Pattern in 3-D

Unit Cell…Unit Cell…Eight points of a crystal lattice.

A parallelopiped… A box(many types)

Polonium

Simple Cubic

Octahedral Coordination

Coordination # = 6

1 Particle per Unit Cell

Sodium

Body-Centered Cubic

Coordination # = 8

2 Particles per Unit Cell

Copper

Face-Centered Cubic

Coordination # = 12

4 Particles per Unit Cell

ABC…ABC…ABC Stacking

XX

X

XX

A

B

C

A

Example Problem…Unit Cell Calculations:

If nickel is cubic close packed and an edge of the unit cell is 352.4 pm, calculate the density of nickel.

Example Problem…Unit Cell Calculations:

If nickel is cubic close packed and an edge of the unit cell is 352.4 pm, calculate the density of nickel.

D= m/VV = [(352.4 pm)(1 cm/1010 pm)]3

V = (3.52 x 10-8 cm)3

m = (4 atoms)(58.7 g/6.02x1023 atoms)m = 3.90x10-22 g

= 3.90x10-22 g/(3.52 x10-8cm)3

=8.94 g/cm3

AB

Cd

sin = AB/d

dsin = AB2dsin = nBragg’s Equation

In diffraction experiments involving silver crystals, info shows that constructive interference of the first order occurs when the angle of the incident x-ray is equal to 14.21° if the wavelength of the radiation is 0.7093 angstroms. What is the inter-atomic spacing of such a crystal (in cm)?

In diffraction experiments involving silver crystals, info shows that constructive interference of the first order occurs when the angle of the incident x-ray is equal to 14.21° if the wavelength of the radiation is 0.7093 angstroms. What is the inter-atomic spacing of such a crystal (in cm)?

2dsin = nd = n2sind = 7.093 x10-9 cm0.4910d = 1.44 x10-8 cm

The Seven Crystal Systems

1. Cubic (isometric) a = b= c = = = 90°

The Seven Crystal Systems

1. Cubic (isometric) a = b= c = = = 90°

Examples: Examples: polonium, sodiumpolonium, sodium

The Seven Crystal Systems

2. Tetragonal a = b= c = = = 90°

Examples: Examples: SnOSnO22, BaSO, BaSO44• 4H• 4H22OO

The Seven Crystal Systems

3. Orthorhombic a = b= c = = = 90°

Examples: Examples: KNOKNO33, FeSO, FeSO44• 7H• 7H22OO

The Seven Crystal Systems

4. Monoclinic a = b= c = = 90° = 90°Examples: Examples: Sugar, CuSOSugar, CuSO44• 5H• 5H22OO

The Seven Crystal Systems

5. Triclinic a = b= c = = = 90°

Examples: Examples: CuSOCuSO44• 5H• 5H22O, O, KK22CrCr22OO77

The Seven Crystal Systems

6. Hexagonal a = b= c = = 90° = 120°Examples: Examples:

Mg, graphiteMg, graphite

The Seven Crystal Systems

7. Rhombohedral (trigonal) a = b= c = = = 90°

Examples: Examples: AgNOAgNO3, 3, CaCOCaCO33

NaCl

Coordination # of 6 for each ion

4 ions of each type per unit cell

ZnS

Coordination # of 4 for each ion

2 ⅓ ions of each type per unit cell

ZnS

Coordination # of 4 for each ion

4 ions of each type per unit cell

Diamond

Coordination # of 4 for each atom

8 atoms per unit cell