International
Tables for Crystallography Volume B Reciprocal space Edited by U. Shmueli © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. B. ch. 4.4, p. 463
Section 4.4.4.4.2. Crystal-H, crystal-K
aDivision of Engineering and Applied Science and The Physics Department, Harvard University, Cambridge, MA 02138, USA |
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 . 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 . In fact, both of these sequences are only intended to indicate the progression in lower symmetry; the actual transitions vary from material to material.