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Figure 6
(a) [001] and (b) 〈[{\overline 3}01]〉 zone-axis EDPs of the disordered defect NaCl-type Mg2+(1−x)Yb2/33+□x/3S (0 ≤ x ≤ 0.45) solid-solution phase. Parts (c) and (d) show equivalent calculated sections through the diffuse surface defined by the equation cos(πh) + cos(πk) + cos(πl) = 0 [shown in part (g); here, q defining the diffuse intensity surface is written as q = ha*+kb*+lc* and h, k and l are continuous variables] from Sauvage & Parthé (1972BB33). Part (e) shows the defect NaCl-type average structure along an 〈001〉 direction and (f) shows the stoichiometrically most common SMg4Yb1□1 local octahedron. The h axis corresponds to the ha* axis, the k axis to the kb* axis and the l axis to the lc* axis in (g).

IUCrJ
Volume 2| Part 1| January 2015| Pages 74-84
ISSN: 2052-2525
doi:10.1107/S2052252514022556