MIXED-VALENCE MOLECULE-BASED COMPOUNDS - CHARGE ORDERING AND MAGNETIC-PROPERTIES

A model of charge ordering in crystals comprising trinuclear mixed-val ence complexes is proposed, Qualitatively different types of temperatu re behaviour of the mean value of crystal dipole moment (order paramet er) are shown to be possible, These types of dependences lead to one, two and three phase transitions, The phase transitions predicted are e lucidated to be of the first and the second kind. The anomalous behavi our of the magnetic moment is shown to arise from non-magnetic electri c dipole-dipole interaction between molecules.