Abstract: It is to provide a liquid crystal composition containing at least one type of optically active compounds of the following formulae (1) to (4), and a liquid crystal electro-optical element excellent in display quality.

Abstract: It is to provide a liquid crystal composition containing at least one type of optically active compounds of the following formulae (1) to (4), and a liquid crystal electro-optical element excellent in display quality. In each formula, C* is asymmetric carbon, and the respective symbols are as defined in description.

Abstract: A difluoroethylene compound of the following formula (1) having a liquid crystal property is provided:R.sup.1 --(A.sup.1).sub.m --Y.sup.1 --A.sup.2 --CF.dbd.CF--A.sup.3 --Y.sup.2 --(A.sup.4).sub.n --R.sup.2 (1)wherein A.sup.1 --A.sup.4, Y.sup.1, Y.sup.2, R.sup.1, R.sup.2, m and n are as defined herein.

Abstract: A difluoroethylene compound of the following formula (1) is provided:R.sup.1 --(A.sup.1).sub.m --Y.sup.1 --A.sup.2 --CF.dbd.CF--A.sup.3 --Y.sup.2 --(A.sup.4).sub.n --R.sup.2 (1)where A.sup.1 -A.sup.4, Y.sup.1, Y.sup.2, R.sup.1, R.sup.2, m and n are as defined herein, and wherein the compound of formula (1) exhibits liquid crystal properties.

Abstract: A difluoroethylene compound of the following formula (1):R.sup.1 --(A.sup.1).sub.m --Y.sup.1 --A.sup.2 --CF.dbd.CF--A.sup.3 --Y.sup.2 --(A.sup.4).sub.n --R.sup.2 (1)wherein A.sup.3 is a trans-1,4-cyclohexylene group, and each of A.sup.1, A.sup.2 and A.sup.4, which are independent from one another, is a trans-1,4-cyclohexylene group or a 1,4-phenylene group, wherein each of such cyclic groups is unsubstituted or substituted by one or more halogen atoms or cyano groups, one or more .dbd.CH-- groups constituting rings of such cyclic groups may be substituted by nitrogen atoms, and one or more --CH.sub.2 -- groups constituting rings of such cyclic groups may be substituted by oxygen atoms or sulfur atoms.

Abstract: A process for producing nucleus-fluorinated aromatic carboxylates, which comprise nucleus-fluorinating aromatic carboxylates of the following formula (1) with a fluorinating agent to obtain nucleus-fluorinated aromatic carboxylates of the following formula (2): ##STR1## wherein R.sup.1 is an alkyl group, an aryl group or a fluoroalkyl group, each of A and B is at least one member selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, an aryl group and a fluoroalkyl group, and n and m are integers satisfying m+n=6, provided that m is 1 or 2, provided that at least one A is an activated chlorine or bromine atom, and B corresponding to such an activated chlorine or bromine atom is a fluorine atom.