Abstract: Liquid crystal compositions comprising as a first part between 40 and 99% by weight in aggregate of one or more materials selected from one or more of the six compound classes (1) to (3'), wherein R is in every instance an alkyl chain containing between 2 and 18 carbon atoms and R' is in every instance an alkyl chain containing between 1 and 17 carbon atoms, wherein one or more non-adjacent CH.sub.2 -groups are replaced by oxygen atoms, and as a second part between 1 and 60% by weight of one or more materials of high birefringence and high positive dielectric anisotropy which raise the S.sub.A -N transition temperature, exhibit a smectic A phase of relatively low melting point and wide smectic range. Such compositions may be used in liquid crystal cells, not only in display or optical information processing applications, but also for instance in temperature sensing applications. The operation of such cells may involve laser addressing, thermal or electrical addressing.

Abstract: A fluorinated compound having a formula: ##STR1## R.sub.1 is hydrogen or alkyl having up to 12 carbon atoms; R.sub.2 is selected from hydrogen, alkyl having up to 12 carbon atoms, alkoxy having up to 12 carbon atoms, ##STR2## wherein R.sub.3 is hydrogen or alkyl having up to 12 carbon atoms, and wherein R.sub.4 is hydrogen, alkyl having up to 12 carbon atoms or alkoxy having up to 12 carbon atoms; ##STR3## represents a cyclohexane ring which is in the trans configuration if 1, 4-disubstituted; ##STR4## represents a benzene ring; each of X, Y and Z independently represents hydrogen or fluorine in one or more of the lateral benzene ring positions, provided that at least one of X, Y and Z is present representing fluorine;n=0 or 1 provided that when n=0 ##STR5## and R.sub.1 is alkyl; with the proviso that in Formula I when n is 1 and ##STR6## where R.sub.1 is n-alkyl and R.sub.2 is n-alkyl or n-alkoxy the total number of carbon plus oxygen atoms in the two groups R.sub.1 and R.sub.2 is less than 10.