Electron microscopy
I4/mmm (139) Space Group
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Table 3000. I4/mmm (139) space group.

Name in the International Tables for Crystallography
I4/mmm I
139 4/mmm
Crystal system
Tetragonal 4/mmm
0 ≤ x ≤ 1/2 and 0 ≤ y ≤ 1/2 and 0 ≤ z ≤ 1/4 and x ≤ y
Symmetry (atomic coordinates)
X, Y, Z; -X, -Y, Z; -Y, X, Z; Y, -X, Z; -X, Y, -Z; X, -Y, -Z; Y, X, -Z; -Y, -X, -Z; -X, -Y, -Z; X, Y, -Z; Y, -X, -Z; -Y, X, -Z; X, -Y, Z; -X, Y, Z; -Y, -X, Z; Y, X, Z; 1/2+X, 1/2+Y, 1/2+Z; 1/2-X, 1/2-Y, 1/2+Z; 1/2-Y, 1/2+X, 1/2+Z; 1/2+Y, 1/2-X, 1/2+Z; 1/2-X, 1/2+Y, 1/2-Z; 1/2+X, 1/2-Y, 1/2-Z; 1/2+Y, 1/2+X, 1/2-Z; 1/2-Y, 1/2-X, 1/2-Z; 1/2-X, 1/2-Y, 1/2-Z; 1/2+X, 1/2+Y, 1/2-Z; 1/2+Y, 1/2-X, 1/2-Z; 1/2-Y, 1/2+X, 1/2-Z; 1/2+X, 1/2-Y, 1/2+Z; 1/2-X, 1/2+Y, 1/2+Z; 1/2-Y, 1/2-X, 1/2+Z; 1/2+Y, 1/2+X, 1/2+Z
Crystal examples
MoSi2: Mo at 0, 0, 0 and Si at 0, 0, 1/3.
Nb4N3, Bi2.2Sr0.8Nb1.9Sc0.1O9


Electron diffraction pattern obtained from Zr41Ti14Cu12.5Ni10Be22.5 in [100] zone axis
[100] Zr41Ti14Cu12.5Ni10Be22.5.
(a = 0.34 nm, and c = 1.137 nm) [1]

Figure 3000. Examples of indexed electron diffraction (or FFT) patterns of I4/mmm (139) crystals.




[1] Q. Wei, N. Wanderka, P. Schubert-Bischoff, and M-P. Macht, S. Friedrich, Crystallization phases of the Zr41Ti14Cu12.5Ni10Be22.5 alloy after slow solidification, J. Mater. Res., 15 (8) 1729, (2000).


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