New 1,3-dioxane type ionic liquid crystal materials having a terminal doubl
e bond were synthesized. The mesomorphic behaviour of these compounds was m
easured. The principal features of these compounds are a smectic A phase ov
er a very wide range including room temperature, and a low isotropic to mes
ophase transition temperature (for example, compound 6-1: Cr-22 SmA 25 I).