The invention relates to CF2O-bridged cyclohexane derivatives, in particular compounds of formula (I), R1-(-A1-Z1-)k1-Q-CF2O-A2-(-Z3-A3-)K3-R2, wherein Q represents group (a); W1, W2 represent —CH2— and/or —O— independendy from each other, X1, X2, X3, X4 represent H, F, —CH3—CH2F—CH2F and/or —CF3 independently from each other, provided that at least one substituent X1, X2, X3 and/or X4 does not represent H, Z2 represents a simple bond, —CH2—CH2— or —CF2—CF2—, m represents 0 or 1 and R1, R2, A1, A2, A3, Z1, Z3, k1 and k3 have the meaning cited in the description. The invention further relates to liquid crystal substances such as optical and electro-optical display elements.