| 摘要 |
<p>Liquid-crystal compounds which exhibit an extremely high voltage retention scarcely dependent on the temperature and a large Δn value and are excellent in the compatibility with other liquid-crystal materials particularly at low temperature; liquid-crystal compositions containing them; and liquid-crystal display elements made by using the compositions. The liquid-crystal compounds are represented by general formula (1), wherein R is C2-C20 alkyl in which one to three arbitrary hydrogen atoms are replaced by fluorine atoms, alkoxy or alkoxyalkyl; X is halogeno or C1-C20 alkyl in which arbitrary methylene groups (-CH2-) not adjacent to each other may be replaced by oxygen atoms or one or more arbitrary hydrogen atoms may be replaced by fluorine atoms; Z1, Z2 and Z3 are each independently -(CH2)2-, -(CH2)4-, -CH2O-, -OCH2-, -(CH2)3O-, -O(CH2)3- or a covalent bond; Y1 to Y16 are each independently hydrogen or fluoro, provided at least two of them are each fluoro; and m is 0 or 1, with the proviso that the atoms constituting the compounds may be each replaced by an isotope thereof.</p> |
