crystallographicplanesanddirections-160606162028

CRYSTALLOGRAPHIC
PLANES AND DIRECTIONS
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Author: Nicola Ergo

Plan
1. Introduction
1.1 Point coordinates
1.2 Example point coordinates
2. Crystallographic directions
2.1 Definition
2.2 Examples
3. Crystallographic planes
3.1 Definition
3.2 Examples
4. Summary
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1. Introduction
When dealing with crystalline materials, it often becomes necessary
to specify a particular point within a unit cell, a crystallographic
direction, or some crystallographic plane of atoms.
Three numbers or indices are used to designate point locations,
directions,and planes.
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1. Introduction
The basis for determining index values is the unit cell, with a right-
handed coordinate system consisting of three (x,y,and z) axes
situated at one of the corners and coinciding with the unit cell edges,
as shown in figure.
A unit cell with x, y, and z coordinate axes,
showing axial lengths (a, b,and c) and
interaxial angles (α, β,and γ). 4
Lattice parameters of crystal structure.

1. Introduction
On this basis there are seven different possible combinations of a,b,and
c,and α,β,and γ,each of which represents a distinct crystal system.
These seven crystal systems are cubic, tetragonal, hexagonal,
orthorhombic, rhombohedral, monoclinic,and triclinic.
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