Liquid crystal compound, liquid crystal composition and liquid crystal display device

A compound represented by formula (1):

• wherein, in formula (1), R1 is alkyl having 1 to 20 carbons, and in the alkyl, arbitrary —CH2— may be replaced by —O— or —S—, and arbitrary —CH2CH2— may be replaced by —CH═CH—;
• ring A1 is independently 1,4-cyclohexylene, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl, pyrimidine-2,5-diyl, pyridine-2,5-diyl, 1,4-phenylene, or 1,4-phenylene in which arbitrary hydrogen is replaced by halogen;
• ring B1 is independently 1,4-phenylene, 3-fluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene, 3-chloro-1,4-phenylene or 3-chloro-5-fluoro-1,4-phenylene;
• Z1 and Z2 are independently a single bond, —CH2CH2—, —CH═CH— or —C≡C—;
• L2, Y1 and Y2 are independently hydrogen, fluorine or chlorine;
• X1 is hydrogen, halogen, —C≡N, —N═C═S, —SF5— or alkyl having 1 to 10 carbons, and in the alkyl, arbitrary —CH2— may be replaced by —O— or —S—, and arbitrary —CH2CH2— may be replaced by —CH═CH—, and arbitrary hydrogen may be replaced by halogen;
• m is 1 or 2;
• n is 1;
• and L1 is fluorine.