Abstract: Compounds of the formula (I)R.sup.1 --(A.sup.1).sub.a (--M.sup.1).sub.b --(--A.sup.2).sub.c (--M.sup.2).sub.d (--A.sup.3).sub.e (--M.sup.3).sub.f (--A.sup.4).sub.g --H(I)in which the symbols and indices have the following meanings:R.sup.1 is B or a straight-chain or branched alkyl radical having 1 to 22 carbon atoms (with or without an asymmetrical carbon atom) in which, in addition, it is possible for one or two non-adjacent --CH.sub.2 -- groups to be replaced by --O--, --S--, --CO--, --CO--O--, --O--CO--, --CO--S--, --S--CO--, --O--CO--O--, --CH.dbd.CH--, --C.tbd.C--, .DELTA. or --Si(CH.sub.3).sub.2 --, and in which, in addition, one or more hydrogen atoms of the alkyl radical may be substituted by F, Cl, Br or CN, or is a chiral group, for example an epoxide, a dioxolane or a cyclic lactone,--(A.sup.1).sub.a (--M.sup.1).sub.b --(--A.sup.2).sub.c (--M.sup.2).sub.d (--A.sup.3).sub.e (--M.sup.3).sub.f (--A.sup.4).sub.

Abstract: Novel oxiranylmethyl ethers can advantageously be employed in liquid-crystal mixtures since they have high spontaneous-polarization values and features in their molecular structure which make them miscible with other components of liquid-crystal systems.

Abstract: 2-Fluoropyrazines, process for their preparation, and their use in liquid-crystalline mixturesA 2-fluoropyrazine of the formula (I) ##STR1## in which the symbols have the following meanings: R.sup.1 and R.sup.2, independently of one another, are, for example, H or straight-chain or branched alkyl,A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are identical or different and are, for example, 1,4-phenylene orM.sup.1, M.sup.2, M.sup.3 and M.sup.4 are identical or different and are, for example, --0-- or --CO--O--,R.sup.3, R.sup.4, R.sup.6 and R.sup.7, independently of one another, are, for example, H or straight-chain or branched alkyl,M.sup.5 is, for example, --O--CO-- or a single bond,k, l, m, n, o, p, q and r are zero or one, with the condition that the sum of k+m+p+r is less than 4 and greater than zero,can advantageously be employed as a component in liquid-crystal mixtures.

Abstract: A 3-fluoropyridine of the formula (I) ##STR1## in which the symbols have the following meanings: R.sup.1 and R.sup.2, independently of one another, are, for example, H or straight-chain or branched alkyl, A.sup.1, A.sup.2, A.sup.3 and A.sup.4 are identical or different and are, for example, 1,4-phenylene, pyrazine-2,5-diyl or trans-1,4-cyclohexylene, M.sup.1, M.sup.2, M.sup.3 and M.sup.4 are identical or different and are, for example, --O-- or --CO--O--, R.sup.3, R.sup.4, R.sup.6 and R.sup.7, independently of one another are, for example, H or straight-chain or branched alkyl, M.sup.5 is for example, --O--CO-- or a single bond, k, l, m, n, o, p, q and r are zero or one, with the proviso that the sum k+m+p+r is less than 4 and greater than zero, can advantageously be employed as a component in ferroelectric liquid-crystal mixtures.

Abstract: Ferroelectric liquid crystal display comprising outer substrates, electrodes, polarizer(s), ferroelectric liquid crystalline material and alignment layer(s), in which the ferroelectric liquid crystalline material has a spontaneous polarization of Ps>20 nC.cm.sup.-2 and a natural helical pitch of less than half of the cell thickness, and the alignment layer comprises at least one lipophilizing, lipophilic and/or amphiphilic compound. The liquid crystal display according to the invention exhibits a short switching time and a significantly reduced surface memory effect, and thus achieves an improved display contrast.

Abstract: Azetidinones of the formula I ##STR1## in which, for example, R.sup.1 is an alkyl or alkenyl radical, R.sup.2 and R.sup.3 are hydrogen or an alkyl or alkenyl radical, Z is hydrogen or (pseudo)halogen, A.sup.1, A.sup.2 and A.sup.3 are a ring system, and M is a spacer group, can be added to liquid-crystal mixtures. Even when admixed in small amounts, they cause considerable twist in the cholesteric and smectic C* phase, which can compensate the pitch of another dope or produce a short S.sub.C * pitch.

Abstract: Electro-optical display devices having a cell thickness of 1 to 10 .mu.m, and containing ferroelectric liquid crystalline mixture, electrodes, alignment layer(s), in which the ferroelectric liquid crystalline mixture has a spontaneous polarization of Ps>20nC.cm.sup.-2 and a natural helical pitch of less than a half of the cell thickness, and contains lipophilizing, lipophilic or amphiphilic compounds for eliminating ionic impurities, Ferroelectric liquid crystal compositions according to the invention show a significantly reduced surface memory effect and an improved display contrast.