Crystalline Solids

Crystalline Solids

p. 459

Macroscopic structure depends upon microscopic structure.

Fluorite (CaF2) Amethyst (SiO2) – quartz+ Fe & Mn

Pyrite (FeS2, fool’s gold)

Crystal terms• Crystal – • Lattice – • Unit cell – • Edge length (do) –

corner

edgeface

• Atoms and ions are represented by spheres.• The spheres stack in different patterns three-

dimensionally.• The close packing of spheres maximizes intermolecular

force.• The patterns of stacking result in different types of unit

cells and lattices.

Packing in Crystals

Lattice – unit cell relationship

Close packing

Close packing unit cell types

Intermetallic Compounds

Alloys

What about the lattice space left over?

NaCl