From OHBA(Japanese)









B2 martensite

DO3 martensite



Laves phase



Crystal Structures

   Knowlwdge of crystal structure is important for discussing or understanding properties of materials. Mechanical properties are related to behavior of atoms, dislocations, twins, boundaries and etc. Electronic structure, which is used to explain the electronic properties, optical properties and etc., cannot be obtained without the knowledge of crystal structure.
  Some of crystal structures are drawn.  Select the above and Click, if you want to see the crystal structures.   
  Figures are drawn with using program, ATOMS.

 Strukturbericht and Pearson Symbol

  Strukturbericht symbol, such as A2, B2, ... etc, is sometimes used for identifying a crystal structure.  Elements is symbolized to be A**, and XY type compound is symbolized B**, XY2 type compound is C**, XmYn type is D** and a compound having more than three elements is E**.  Some examples are listed below.
  The Pearson symbol represents crystal system, type of Bravais lattice and number of atoms in the unit cell. For example, fcc (face centered cubic) structure is cubic system with face centered Bravais lattice involving 4 atoms in the init cell. So Pearson symbol of fcc structure is cF4. The crystal system is abbriviated to be a=triclinic, m=monoclinic, o=orthorhombic, t=tetragonal, h=hexagonal and trigonal and c=cubic. The Bravais lattice is represented to be P, S (for A, B and C), R, F and I.   

Crystal structure Strukturbericht symbol Pearson symbol
fcc A1 cF4
bcc A2 cI2
hcp A3 hP2
Diamond (C) A4 cF8
White Tin (Sn) A5 tI4
aAs A7 hR2
Graphite (C) A9 hP4
a-Mn A12 cI58
b-W (WO3) A15 cP8
NaCl B1 cF8
CsCl B2 cP2 L20 is found in some textbook, but does not appeare in Pearson's Handbook.
ZnS (sphalerite) B3 cF8
ZnO (wurtzite) B4 hP4
AuCd (orthorhombic) B19 oP4
FeSi B20 cP8
CrB Bf oC8
CaF2 C1 cF12
FeS2 (pyrite) C2 cF12
Cu2O (cuprite) C3 cP6
TiO2 (rutile) C4 tP6
SiO2 (high quartz) C8 hP9
SiO2 (b cristobalite) C9 cF24
MoSi2 C11b tI6
MgZn2 C14 hP12
MgCu2 C15 cF24
TiO2(brookite) C21 oP24
AlB2 C32 hP3 Omega phase has this type of structure.
MgNi2 C36 hP24
Fe3Al D03 cF16
ReO3 D09 cP4
Fe3 D011 oP16
Ni3Ti  D024 hP16
a-Al2O3 D51 hR10
Cr3C2 D510 oP20
Co3S4(Linnaeite) D72 cF56 Prototype of Magnetite (Fe3O4)
g-brass (Cu5Zn8) D82 cI52
Cr23C6 D84 cF116 Carbide found in steels. Secondary carbide is reported to have this structure.
s-FeCr D8b tP30
Mn7C3 D101 oP40 Carbide found in steels. Primary carbide is reported to have this structure.
Perovskite (cubic BaTiO3) E21 cP5
AuCu, FePt L10 tP4 If the unit cell is taken different way, Peason symbol becomes tP2.
Cu3Au L12 cP4
Heuisler  (Cu2MnAl) L21 cF16
Spinel (MgAl2O4) H11 cF56

note: b-W (WO3) type structure is symbolized A15, in spite of two elements included, because of historical reason.     


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