Crystalline Solids BLB 12 th Chapter 12 Sections 1-3, 5 Types of
Crystalline Solidsp. 464 Macroscopic structure depends upon
microscopic structure. Fluorite (CaF 2 )Amethyst (SiO 2 ) quartz +
Fe & Mn Pyrite (FeS 2, fools gold) Crystalline atoms, ions, or
molecules arranged orderly Ionic compounds, diamond, sugar, ice
Amorphous without form; lack the order of solids Glass, plastic,
wax, ceramics Crystal Terms Crystal Crytal Lattice Unit cell Cell
dimensions a, b, c, , , corner edge face Crystalline lattice in two
dimensions Crystalline lattice in three dimensions Filling the unit
cell Types of Unit Cells 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 p. 468 Types of cubic unit cells
Body-centered cubic unit cell of C 60 Types of cubic unit cells
Three items to determine for each type: 1.Number of atoms per unit
cell 2.Number of nearest neighbors for each atom 3.Relationship
between sphere radius and the cell edge length, d o ? Primitive
(simple) Cubic _______ atoms per unit cell _______ nearest
neighbors Body-centered Cubic _______ atoms per unit cell _______
nearest neighbors Face-centered Cubic (result of close packing)
_______ atoms per unit cell _______ nearest neighbors Close packing
Close Packing Hexagonal close-packed (hcp) ABAB layers Cubic
close-packed (ccp) ABCABC layers Close packing unit cell types What
about the space left over?
