International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

International Tables for Crystallography (2006). Vol. B, ch. 4.4, p. 463   | 1 | 2 |

Section 4.4.4.4.2. Crystal-H, crystal-K

P. S. Pershana*

aDivision of Engineering and Applied Science and The Physics Department, Harvard University, Cambridge, MA 02138, USA
Correspondence e-mail: pershan@deas.harvard.edu

4.4.4.4.2. Crystal-H, crystal-K

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The crystalline-H and crystalline-K phases are tilted versions of the crystalline-E. The crystalline-H is tilted in the direction between the near neighbours, with the convenient mnemonic that on cooling the sequence of phases with the same relative orientation of tilt to near-neighbour position is [\hbox{F} \rightarrow \hbox{G} \rightarrow \hbox{H}]. Similarly, the tilt direction for the crystalline-K phase is similar to that of the smectic-I and crystalline-J so that the expected phase sequence on cooling might be [\hbox{I} \rightarrow \hbox{J} \rightarrow \hbox{K}]. In fact, both of these sequences are only intended to indicate the progression in lower symmetry; the actual transitions vary from material to material.








































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