Abstract: A liquid crystal compound selected from a group of compounds represented by formula (a): wherein Ra and Rb are each independently alkyl having 1 to 10 carbons, alkoxy having 1 to 9 carbons, alkoxyalkyl having 2 to 9 carbons, alkenyl having 2 to 10 carbons, alkenyloxy having 2 to 9 carbons, fluoroalkyl having 1 to 10 carbons or fluoroalkoxy having 1 to 9 carbons; ring A1, ring A2 and ring A3 are each independently trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, trans-tetrahydropyran-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, 6-fluoropyridine-2,5-diyl or pyridazine-2,5-diyl; Z1, Z2 and Z3 are each independently a single bond, —(CH2)2—, —CH?CH—, —C?C—, —CH2O, —OCH2—, —COO—, —OCO—, —OCF2—, —CF2O—, —CH2CH2OCF2— or —CF2OCH2CH2—; l, m and n are each independently 0, 1 or 2, provided that l+m+n is 0, 1, 2 or 3; one of X1 and X2 is fluorine, and the other is chlorine; Q is and atoms comprising the

Abstract: A liquid crystal compound selected from a group of compounds represented by formula (a): wherein Ra and Rb are each independently hydrogen, alkyl having 1 to 10 carbons or alkenyl having 2 to 10 carbons, provided that in the alkyl, —CH2— may be replaced by —O—, but plural —O— are not adjacent to each other, and hydrogen may be replaced by fluorine; ring A1 and ring A2 are each independently trans-1,4-cyclohexylene or 1,4-phenylene, provided that one or two hydrogens of the 1,4-phenylene may be replaced by halogen, and in a 6-membered ring of these groups, one —CH2— or two —CH2— that are not adjacent to each other may be replaced by —O—, and one or two —CH? may be replaced by —N?; Z1 and Z2 are each independently a single bond, —(CH2)2—, —(CH2)4—, —CH?CH—, —C?—, —CH2O—, —OCH2—, —COO—, —OCO— or —OCF2—; l and m are each independently 0, 1 or 2, provided that l+m is 0, 1, 2 or 3; and n is an integer of from 0 to 6, provided that in —(CH2)n—, —CH2— may be replaced by —O—, but plural —O— are not adjacent to eac

Abstract: What are provided include a liquid crystal composition that satisfies many characteristics among the characteristics such as a wide temperature range of a nematic phase, a suitable optical anisotropy, a negatively large dielectric anisotropy, and a large specific resistance, a liquid crystal composition that satisfies the characteristics and simultaneously has a small optical anisotropy and a low minimum temperature of a nematic phase, and preferably approximately ?20° C. or less, and a liquid crystal display device containing the composition.

Abstract: Such a liquid crystal compound is provided that has stability to heat, light and so forth, has a nematic phase in a wide temperature range, has a small viscosity, a suitable optical anisotropy, and suitable elastic constants K33 and K11 (K33: bend elastic constant, K11: splay elastic constant), and has suitable negative dielectric anisotropy and excellent compatibility with other liquid crystal compounds. A liquid crystal composition containing the liquid crystal compound, and a liquid crystal display device containing the liquid crystal composition are also provided.