Figure 4
Tetragonal lattices (a-b planes, common c axis pointing upwards) of twin domain I (start domain, lattice points small circles, right-handed green unit cell a1, b1, c1), of the [Sigma]5 twin-related domain II (small crosses, left-handed blue unit cell a2, b2, c2) and the [Sigma]5 coincidence lattice (large black points, right-handed red unit cell aT, bT, cT). The four alternative twin reflection planes m'(120), m'(2[\overline 1]0), m'(310) and m'([\overline 1]30) are indicated by dashed lines. The coordinate axes a2, b2, c2 of domain II (blue) are defined by the reflection plane m'(120). The right-handed yellow unit cell a3, b3, c3 of domain II is obtained from a1, b1, c1 by a clockwise rotation of [varphi] = 2 arctan  (1/2) = 53.13° around the tetragonal c axis (cf. Appendix C[link]). This cell is commonly used in structure determinations.  [article HTML]

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