Electron microscopy
Fm-3m (225) Space Group
- Practical Electron Microscopy and Database -
- An Online Book -
Microanalysis | EM Book                                                                                   http://www.globalsino.com/EM/        

This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.


Table 3025a. Fm-3m (225) space group.

Name in the International Tables for Crystallography
Fm-3m F
225 m-3m
Crystal system
Cubic m-3m
Pearson symbol
cF12, cF8, etc. 192
Structure type
NaCl-type structure 1, √3, √4, √8, √11, √12, √16, √19, √20, √24, √27, ...
Symmetry (atomic coordinates)
X, Y, Z; -X, -Y, Z; -X, Y, -Z; X, -Y, -Z; Z, X, Y; Z, -X, -Y; -Z, -X, Y; -Z, X, -Y; Y, Z, X; -Y, Z, -X; Y, -Z, -X; -Y, -Z, X; Y, X, -Z; -Y, -X, -Z; Y, -X, Z; -Y, X, Z; X, Z, -Y; -X, Z, Y; -X, -Z, -Y; X, -Z, Y; Z, Y, -X; Z, -Y, X; -Z, Y, X; -Z, -Y, -X; -X, -Y, -Z; X, Y, -Z; X, -Y, Z; -X, Y, Z; -Z, -X, -Y; -Z, X, Y; Z, X, -Y; Z, -X, Y; -Y, -Z, -X; Y, -Z, X; -Y, Z, X; Y, Z, -X; -Y, -X, Z; Y, X, Z; -Y, X, -Z; Y, -X, -Z; -X, -Z, Y; X, -Z, -Y; X, Z, Y; -X, Z, -Y; -Z, -Y, X; -Z, Y, -X; Z, -Y, -X; Z, Y, X; X, 1/2+Y, 1/2+Z; -X, 1/2-Y, 1/2+Z; -X, 1/2+Y, 1/2-Z; X, 1/2-Y, 1/2-Z; Z, 1/2+X, 1/2+Y; Z, 1/2-X, 1/2-Y; -Z, 1/2-X, 1/2+Y; -Z, 1/2+X, 1/2-Y; Y, 1/2+Z, 1/2+X; -Y, 1/2+Z, 1/2-X; Y, 1/2-Z, 1/2-X; -Y, 1/2-Z, 1/2+X; Y, 1/2+X, 1/2-Z; -Y, 1/2-X, 1/2-Z; Y, 1/2-X, 1/2+Z; -Y, 1/2+X, 1/2+Z; X, 1/2+Z, 1/2-Y; -X, 1/2+Z, 1/2+Y; -X, 1/2-Z, 1/2-Y; X, 1/2-Z, 1/2+Y; Z, 1/2+Y, 1/2-X; Z, 1/2-Y, 1/2+X; -Z, 1/2+Y, 1/2+X; -Z, 1/2-Y, 1/2-X; -X, 1/2-Y, 1/2-Z
Crystal examples
CaF2: Ca at (0, 0, 0) and F at (1/4, 1/4, 1/4).
NaCl: Na at (0, 0, 0) and Cl at (1/2, 1/2, 1/2).
TiN: Ti (1a) at (0, 0, 0), and N (1b) at (0, 0.5, 0)
Crystals in Figure 3025b.

Typical example of X-ray powder diffraction pattern obtained from Fm-3m structures (AgPb6SbTe8, AgPb12SbTe14, AgPb18SbTe20, Ag0.86Pb18SbTe20, AgSbTe2, and PbTe compounds)

Figure 3025a. Typical example of X-ray powder diffraction patterns obtained from Fm-3m single-phase structures (AgPb6SbTe8, AgPb12SbTe14, AgPb18SbTe20, Ag0.86Pb18SbTe20, AgSbTe2, and PbTe compounds). [1] Note that we can index diffraction patterns starting from comparing experimental d-spacings and theoretical calculations obtained from known lattice parameters, for instance, use the excel file for crystals with Fm-3m space group.

A [001] diffraction pattern obtained from Ag0.95Pb15SbTe17 (space group: Fm-3m)
Electron diffraction pattern obtained from [001] Ag0.95Pb15SbTe17 (space group: Fm-3m) with splitting of electron reflections
[0 0 1] Ag0.95Pb15SbTe17.
(a = 0.64 nm) [1]
[0 0 1] Ag0.95Pb15SbTe17
with diffuse streaks. [1]
[001] Ag0.95Pb15SbTe17
with splitting of electron reflections. [1]
[0 0 1] Ge2Bi2Te5
4mm net symmetry in ZOLZ in [001] zone-axis of Zr41Ti14Cu12.5Ni10Be22.5
[0 0 1] Ge2Bi2Te5. [3]
4mm net symmetry in ZOLZ [001] zone-axis of Zr41Ti14Cu12.5Ni10Be22.5 ( a = 1.185 nm) [4]  
indexed electron diffraction patterns of FCC crystals
[1 1 0] Ge2Bi2Te5
[0 1 1] Ag0.95Pb15SbTe17.
(a = 0.64 nm) [1]
[1 1 0] Ge2Sb2Te5 (GST). [2]
[1 1 0] Ge2Bi2Te5. [3]
Indexed Electron Diffraction Patterns of FCC Crystals GST
[-1 1 1] Ge2Sb2Te5 (GST). [2]
[1 1 1] Ag0.95Pb15SbTe17.
(a = 0.64 nm) [1]
[-1 1 2] Ag0.95Pb15SbTe17.
(a = 0.64 nm) [1]

Figure 3025b. Examples of indexed electron diffraction (or FFT) patterns of Fm-3m (225) cubic crystals.




[1] Eric Quarez, Kuei-Fang Hsu, Robert Pcionek, N. Frangis, E. K. Polychroniadis, and Mercouri G. Kanatzidis, Nanostructuring, Compositional Fluctuations, and Atomic Ordering in the Thermoelectric Materials AgPbmSbTe2+m. The Myth of Solid Solutions, J. AM. CHEM. SOC. 127, 9177-9190, 2005.
[2] J.J. Zhao, F.R. Liu, X.X. Han, Z. Zhu, X. Lin, F. Liu, N.X. Sun, Transmission electron microscopy study of amorphous Ge2Sb2Te5films induced by an ultraviolet single-pulse laser, Applied Surface Science 311 (2014) 83–88.
[3] Chang Woo Sun, A Transmission Electron Microscopy Study on the Microstructural Properties of Te-based Chalcogenide Thin Films, Doctoral Thesis, 2010.
[4] 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).



The book author (Yougui Liao) welcomes your comments, suggestions, and corrections, please click here for submission. If you let book author know once you have cited this book, the brief information of your publication will appear on the “Times Cited” page.