| abstract |
Liquid crystal compounds which exhibit a liquid crystal phase in a wide temperature range and are lowly viscous and excellent in chemical stability and compatibility with other liquid crystal materials; liquid crystal compositions containing the compounds; and liquid crystal display devices made by using the compositions. The above liquid crystal compounds are represented by the general formula (1): Ra-A1-Z1-A2-Z2-A3-Z3-A4-Rb wherein Ra is alkenyl or alkyl wherein one or more methylene groups may be replaced by -O-, -S-, -CO-, -C C- and so on; Rb is Ra, halogeno or cyano, with the proviso that at least either of Ra and Rb must be a group containing a double bond; A1, A2, A3 and A4 are each independently trans-1,4-cyclohexylene, 1,4-phenylene, cyclohexenediyl, pyridine-2,5-diyl, pyrimidine-2,5-diyl or 1,3-dioxane-2,5-diyl; and Z1, Z2 and Z3 are each independently C2-C4 alkenylene, -(CH2)2-, -COO-, -C C-, -CH2O-, a single bond or the like, at least one of Z1, Z2 and Z3 being C2-C4 alkenylene. |