Liquid crystal compounds and compositions.

摘要

Smetic C liquid crystal compounds, represented by the following formula (1) or (2) are disclosed. <CHEM> wherein R<1> and R<2> are C1-18 alkyl groups; A is a cyclic group, such as aubstituted or unsubstituted 1,4-phenylene group, <CHEM> X is direct bond, O or C IDENTICAL C; Y is -C IDENTICAL C- or -CH2CH2-; one of A<1> and A<2> is 1,4-phenylene group and the other is 2,3-difluoro-1,4-phenylene group; and p is 0 or 1. These compounds can provide ferroelectric liquid crystal composition of low viscosity, and are useful as a component giving negative dielectric anisotropy and enlarging a temperature range showing smetic C phase.