Liquid crystalline alkenyl cyclohexane compounds of formula (I) having a nematic phase over a broad temperature range, a higher elastic constant ratio K.sub.33 /K.sub.11 and a lower viscosity, liquid crystal compositions comprising the above compounds and liquid crystal display elements using the liquid crystal compositions. ##STR1## wherein R.sub.1 is an alkyl group of 1-15 carbons, an alkenyl group of 2-15 carbons or an alkyl or alkenyl group in which at least one of non-adjacent methylene groups (--CH.sub.2 --) is replaced by --O--, --S--, --C.tbd.C-- or --COO--; R.sub.2 is a hydrogen atom or an alkyl group of 1-10 carbons; m is 0-5; when m is 2 or more, any one methylene group in --(CH.sub.2).sub.m -- may be replaced by --O--; and the rings A.sub.1, A.sub.2 and A.sub.3 are independently a 1,4-cyclohexylene, a cyclohexene-1,4-diyl or a 6-membered ring group, one or two --CH.sub.2 -- groups in said rings optionally replaced by --O-- or --S--.
公式 (I) 中的液晶烯基
环己烷化合物具有宽温度范围内的向列相、更高的弹性常数比K.sub.33 /K.sub.11和更低的粘度,液晶组合物包括上述化合物和使用液晶组合物的液晶显示元件。其中 R.sub.1是1-15个碳的烷基、2-15个碳的烯基或至少有一个非相邻甲基基团(--CH.sub.2 --)被替换为--O--、--S--、--C.tbd.C--或--COO--的烷基或烯基基团;R.sub.2是氢原子或1-10个碳的烷基基团;m为0-5;当m为2或更多时,--(CH.sub.2).sub.m --中的任何一个甲基基团可以被--O--替换;环A.sub.1、A.sub.2和A.sub.3分别独立为1,4-环己基、
环己烯-1,4-二基基团或6-环基团,该环中的1或2个--CH.sub.2--基团可以选择性地被--O--或--S--替换。