Abstract: The invention relates to pyridine derivatives of the formula I ##STR1## wherein R.sup.1, A.sup.1, E.sup.1, n, A.sup.2, Z.sup.2, X and Y have the meaning given in claim 1.

Abstract: 4-Q.sup.1 -4'-Q.sup.2 -2,3-Difluorobiphenyls whereinQ.sup.1 and Q.sup.2 independently of one another are each R or R-A.sup.1 -A.sup.2 -Z in whichR (sic) alkyl having 1-15 C atoms or alkenyl having 3-15 C atoms each of which is unsubstituted or monosubstituted by cyano or at least monosubstituted by fluorine or chlorine, and in which in each case one or two non-adjacent CH.sub.2 groups can also be replaced by --O--, --CO--, --O--CO, --CO--O-- or --O--COO--, (sic) --COO--, --O--CO--, --CH.sub.2 O, --O--CH.sub.2 --, --CH.sub.2 CH.sub.2 -- or a single bond, andA.sup.1 and A.sup.2 independently of one another . . (sic) each 1,4-phenylene which is unsubstituted or substituted by one or two fluorine atoms, and in which one or two CH groups can also be replaced by N, or trans-1,4-cyclohexylene wherein one or two non-adjacent CH.sub.2 groups can also be replaced by --O--, and one of the two groups A.sup.1 and A.sup.2 can also be a single bond,subject to the proviso that Z is --CO--O, --O--CO--, --CH.sub.2 O--, --OCH.

Abstract: Chiral, tilted, smectic liquid-crystal phases containing at least two liquid-crystal components and at least one chiral doping agent, at least one liquid-crystal component being a compound having the structural unit 2,3-difluoro-1,4-phenylene, are distinguished by a very low viscosity and advantageous switching times.

Abstract: Chloro tolanes of the formula I ##STR1## wherein R.sup.1 denotes alkyl with up to 12 carbon atoms wherein one or two non-adjacent CH.sub.2 groups may also be replaced by --O--, --O--CO--, --CO--O-- and/or --CH.dbd.CH--,A is trans-1,4-cyclohexylene or 1,4-phenylene,r is 0 or 1,s is 0 or 1,L.sup.1 and L.sup.2 are H or F,whereby one of the substituents L.sup.1 and L.sup.2 is F and the other is H or F and if s is 0 and R.sup.1 is alkyl having 2 to 12 carbon atoms both L.sup.1 and L.sup.2 may be Hare suitable as components of liquid crystalline media.

Abstract: Four ring esters and ethers of formula I ##STR1## wherein R.sup.1 and R.sup.2 independently from each other are alkyl or alkenyl with up to 9 carbon atoms or such residues wherein one CH.sub.2 group is replaced by oxygen,m and n are each 1 or 2, the sum of m and n being 3,X.sup.1 and X.sup.2 are each hydrogen or fluorine, andQ is --CH.sub.2 -- or --CO--with the proviso that in case m=2 Q is --CH.sub.2 -- and/or at least one of X.sup.1 and X.sup.2 is F are suitable as components of liquid crystal media.

Abstract: A chiral, tilted, smectic liquid crystal phase comprising a mixture of at least two compounds, wherein at least one compound is an achiral fluorinated biphenyldiole compound of formula I ##STR1## whereinR.sup.1 and R.sup.2 are each independently alkoxy or alkanoyloxy with 1 to 15 C atoms, ##STR2## denotes a 4,4-phenylene group optionally substituted by up to four F atoms, and is 1.

Abstract: Novel cyanohydrin derivatives of general formula (I) wherein R.sup.1 is hydrogen, alkyl, alkoxy, perfluoroalkyl or perfluoroalkoxy, R.sup.2 is alkyl, r is 1 to 10, n and m are 0 or 1, provided if both n and m are 0 then X is (II) or (III), where (F) indicates one or more optional fluorines, p is 0 or 1, Z is a single bond if p is 0 and COO if p is 1; and if one or both of n or m are 1 then X is (IV), where each ring A, B and C is phenyl, fluoro- or chloro-phenyl, cyclohexyl, pyrimidyl, pyridyl, or dioxanyl, A, B and C are single bonds or linking groups, and (a+b+c) is 2 or 3. Liquid crystal materials containing these compounds are also described.

Abstract: Biphenylylethanes of the formula I,R.sup.1 --CH.sub.2 --X--(CH.sub.2 CH.sub.2).sub.m --Ph--Ph--CH.sub.2 CH.sub.2 --Ph--Y--CH.sub.2 --R.sup.2 Iin whichR.sup.1 and R.sup.2 are each, independently of one another, alkyl, alkenyl or oxaalkyl having up to 12 C atoms, and one of the radicals R.sup.1 and R.sup.2 is alternatively H,m is 0 or 1,X and Y are each, independently of one another, O, S, CO--O, O--CO, O--CO--O or a single bond, the radical X is alternatively 1,4-phenylene or trans-1,4-cyclohexylene, and the radical Y is alternatively trans-1,4-cyclohexylene, andis 1,4-phenylene, and one or two of the radicals Ph is alternatively 2- or 3-fluoro-1,4-phenylene,with the proviso that, in the case (a) where X=1,4-phenylene and m=1, one or two of the radicals Ph are 2- or 3-fluoro-1,4-phenylene, and (b) in the case where X=trans-1,4-cyclohexylene, m=0 and one or two of the radicals Ph are 2- or 3-fluoro-1,4-phenylene, are suitable as components of liquid-crystalline phases.