Electron microscopy
  
Pearson Symbols
- Practical Electron Microscopy and Database -
- An Online Book -
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Pearson symbol represents crystal system, type of Bravais lattice and number of atoms in an unit cell. For instance, a face-centered cubic (FCC) structure is a face-centered Bravais lattice having 4 atoms in the unit cell, and thus its Pearson symbol is cF4. In this notation, the crystal system is simplified by a = triclinic, m = monoclinic, o = orthorhombic, t = tetragonal, h = hexagonal and trigonal and c = cubic. The Bravais lattice is symbolized by P, S (for A, B and C), R, F and I.

Table 2954a. Symbols used in Pearson notation.

Pearson symbol
Crystal system
Bravais lattice

aP

Triclinic (anorthic) aP
mP
 Simple monoclinic mP
mC
 Base-centered monoclinic mS (formerly mA, mB, mC)*
oP
Simple orthorhombic oP
oC
 Base-centered orthorhombic oS (formerly oA, oB, oC)*
oF
Face-centered orthorhombic oF
oI
 Body-centered orthorhombic oI
tP
 Simple tetragonal tP
tI
 Body-centered tetragonal tI
hP
 Hexagonal hP
hR
 Rhombohedral hR
cP
 Simple cubic cP
cF
 Face-centered cubic cF
cI
 Body-centered cubic cI
* The face that has a lattice point at its center may be chosen as the c face (xy plane), denoted by the symbol C, or as the a or b face, denoted by A or B, since the choice of axes is arbitrary. The letter S has been recommended by a subcommission of the International Union of Crystallography.

Table 2954b. Other characteristics of Pearson notations.

Characteristics
Page
Relationship between Strukturbericht notation, Pearson symbol and space group page2955

 

 

 
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