Ester derivative having a positive dielectric anisotropy

摘要

A novel ester derivative affording a positive large dielectric anisotropy value ( DELTA epsilon ) of liquid crystal compositions and also reducing the optical anisotropy value ( DELTA n) thereof when the derivative is contained therein, and a liquid crystal composition containing the ester derivative are provided, which ester derivative is expressed by the formula <IMAGE> wherein R represents an alkyl group or an alkoxy group each of 1 to 10 carbon atoms and X represents F or Cl.