Halides magnetic properties

Apart from TiO and the lower halides already mentioned, the chemistry of these metals in oxidation states lower than 3 is not well established. Addition compounds of the type [TiCl2L2] can be formed with difficulty with ligands such as dimethylformamide and acetonitrile, but their magnetic properties suggest that they also are polymeric with appreciable metal-metal bonding. However, the electronic spectra of Ti in TiCl2/AlCl3 melts and also of Ti incorporated in NaCl crystals (prepared by... 

Relationships between covalency, interatomic distances and magnetic properties in halides and chal-cogenides. R. D. Shannon and H. Vincent, Struct. Bonding (Berlin), 1974,19,1-43 (50). 

Shannon, R. D., Vincent, H. Relationship Between Covalency, Interatomic Distances, and Magnetic Properties in Halides and Chalcogenides. Vol. 19, pp. 1-43. 

Relations between the structure and properties have been investigated in a variety of solids such as metal oxides, chalcogenides, pnictides and halides. In addition to studying model systems for testing theoretical predictions, solid state chemists have been preparing new classes of solids as well as novel members of known types of solids. In this section, we have chosen three classes of solids, viz. metal oxides, metal sulphides and metal fluorides, to discuss structure-property relations we shall concentrate especially on their electrical and magnetic properties. 

These uncertainties are increased when the existence of compounds of CO with metals, the carbonyls such as Fe(CO)5, for which no electrostatic model is conceivably possible are considered. The iron obviously is not present in the compound as an ion how then can the attraction for the CO molecules be explained Even in the straight ammoniates there is some doubt regarding the validity of the simple electrostatic representation of the structure for it is found experimentally that the magnetic properties of halides are radically altered by the taking up of molecules of ammonia. This shows that - some of the electrons of the positive ions are influenced by the ammonia molecules in a way which an electrostatic picture cannot explain. 

---