An optically active compound having a .delta.-valerolactone ring which is a ferroelectric liquid crystal and is represented by the following general formula (I): ##STR1## wherein m is an integer of from 1 to 8, Z is a group represented by the following formula: ##STR2## in which each of l and k is a number of 1 or 2 and l and k satisfy the requirement of 2.ltoreq.(l+k).ltoreq.3, X stands for a direct bond, ##STR3## Y stands for ##STR4## and A.sub.1 and A.sub.2 independently stand for --H, --F or --Cl, ##STR5## R stands for ##STR6## in which n is an integer of from 1 to 18, and * indicates the asymmetric carbon atom.
具有.delta.-
戊内酯环的光学活性化合物,为
铁电液晶,其通式(I)如下所示:其中m为1至8的整数,Z为以下通式所代表的基团:其中l和k各自为1或2的数字,且l和k满足2≤(l+k)≤3,X代表直接键,Y代表,A.sub.1和A.sub.2独立地代表--H,--F或--Cl,R代表,其中n为1至18的整数,*表示不对称碳原子。