| The following
pages contain descriptions and illustrations of some cubic and hexagonal
crystal lattices and their unit cells.
A lattice is a regular array of lattice points in three
dimensions, and a crystallographic unit cell is a parallelapiped
formed by connecting eight lattice points.
A cubic unit cell is characterized by six square faces and three
equal non-coplanar edges:
a = b = c. The volume of a cubic unit cell is a.b.c
or
V = a3
A hexagonal unit cell is characterized by four rectangular faces
(with edges a & c and b & c) and two parallelograms with equal
sides (a = b) and interior angles of 60o and 120o.
The volume of a hexagonal unit cell is a.b.c.sin(120o)
or
Most of the illustrations in the following pages are crossed-stereo
pairs. To view them, cross your eyes and focus.
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