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SOLZ (second order Laue zones) can be described by the equation given by
hu + kv + lw = 2  [3901a]
where,
[uvw]  The direction of the incident electron beam.
hkl  The coordinates of an allowed reflection in the Nth order Laue zone.
Figure 3901a shows ZOLZ (zeroorder Laue zone), FOLZ (first order Laue zones) and SOLZ.
Figure 3901a. Schematic of ZOLZ, FOLZ, and SOLZ.
However, the structure factors can cause all the reflections in a FOLZ to be forbidden so that the first ring of spots in the experimental diffraction pattern is from the second layer of the reciprocal lattice but we still call the SOLZ as the FOLZ.
According to the discussion in page4783, the radius of the SOLZ rings, G_{2} (nm^{1} or Å^{1}), can be given by,
 [3901b]
where,
λ  The electron wavelength.
H  The spacing of the reciprocal lattice planes parallel to the electron beam (nm^{1} or Å^{1}).
The analysis of Laue zones can provide detailed information regarding the samples. For instance, √2TTB phase of Pb_{x}Nb_{1.17}W_{1.0}O_{5.93+x} (x > 0.15) in Figure 3901b presented asymmetric electron diffraction patterns and exhibited systematically weak oddorder (First order here) Laue layers lying halfway between the positions of the strong evenorder (zero and second order here) layers. The evenorder layers correspond to the basic 3.8 Å c_{TTB} (c axis of TTB structure) repeat. Analyses of multiple samples indicate that these weak oddorder reflections were present in the same positions as the maxima in the even layers and at the midpoint of each edge of the basic TTB square.
Figure 3901b. Asymmetric diffraction pattern of the √2TTB phase of Pb_{x}Nb_{1.17}W_{1.0}O_{5.93+x} (x > 0.15). The inset enlargement of the firstorder Laue layer shows that the black mesh defines the √2TTB reciprocal lattice periodicity [2], and the dashed square illustrates the position of the basic TTB cell repeat with respect to the √2TTB cell.
Adapted from [1]
[1] Sarah K. Haydon and David A. Jefferson, Quaternary LeadNiobiumTungsten Oxides Based on the Tetragonal Tungsten Bronze Structure, Journal of Solid State Chemistry 161, 135  151 (2001).
[2] S. K. Haydon, Ph.D. Thesis, University of Cambridge, 2000.
