The invention relates to fluorinated fluorene derivatives of negative DC anisotropy, of the formula I R1—(—A1—Z1—)k1—(—A2—Z2—)k2—W—(—Z3—A3—)k3—(—Z4—A4—)k4—R2I in which W denotes the sub-formula L1 and L2, independently of one another, are H, F, Cl, —CH2F, —CHF2 or —CF3, with the proviso that L1 and L2 are not both H, L3 and L4, independently of one another, are H or F, and R1, R2, A1, A2, A3, A4, Z1, Z2, Z3, Z4, k1, k2, k3 and k4 are as defined above. The invention furthermore relates to liquid-crystalline media and to optical and electro-optical display elements.