  Liquid crystal materials exhibiting up to three nematic phases are reported.
Dielectric response measurements show that while the lower temperature nematic
phase has ferroelectric order and the highest temperature nematic phase is
apolar, the intermediate phase has local antiferroelectric order. The
modification of the molecular structure by increasing the number of lateral
fluorine substituents leads to one of the materials showing a direct
isotropic-ferronematic phase transition.
