Transition Metal Dichalcogenides and Their Intercalates

The transition metal dichalcogenides form a group of layered, highly anisotropic compounds which exhibit interesting and unusual physical properties. Compounds formed from the Group Iv, Group V and Group VI transition metals and from sulphur or selenium have been the subject of a great deal of interest in the past few years because of the possibility of introducing foreign species between the layers and causing many of the properties of the host lattice to change in a predictable way, consistent with the rigid band model. The most common intercalate complexes are those formed from alkali metals, Lewis bases and transition and post-transition metals. In this review a number of these compounds are discussed, with special emphasis on those which provide new information about the host material, or where some new, interesting property of the complex has been demonstrated.