In quasi-one-dimensional (TMTTF)2X
conductors [1], where X are the various centro-symmetrical and
non-centrosymmetrical anions, by study of temperature dependences of conductance
G and dielectric permittivity $\varepsilon '$
at low frequencies we have found anomalies which are characteristic for phase transitions: an abrupt bend on the
G(l/T) dependences with thermally activated decrease of G and sharp maxima of the E' near the charge ordering
temperature corresponding to the E' divergence according to the Curie law. A number of evidences have been
obtained in favor that driving force of these phase transitions is the long range correlated electron interaction
yielding the charge ordering along the molecular chains (a lattice version of the Wigner crystal). The anion chains,
electrically balanced with molecular chains, are of very importance in the formation and the stabilization of these
new phase states. It appears that the form of charge symmetry of the anions determines to a great extent the types of
the occurring transitions and the developing ground states.
Quantum phase transitions in a quasi-one-dimensional Ising quantum magnet in transverse fields