Metallic Tl2TeO6 and insulating In2TeO6 are both known to crystallize in the Na2SiF6-type structure. We have now prepared a complete Tl2-xInxTeO6 series in a search for a compositionally controlled metal-insulator transition that might be expected if a complete solid solution can be obtained. Unit cell edges and volume vary monotonically with no indication of miscibility gap. The metal-insulator transition occurs at an x value of about 1.4, which can be rationalized on a percolation model. No superconductivity could be detected down to 5K.
Rh2MO6, M = Mo, W, and Te were synthesized by solid state reaction. Electronic properties as well as thermoelectric properties were investigated and discussed. The compounds crystallize in rutile-related structure and all show relatively
high electronic conductivities with Rh2TeO6 showing the highest electronic conductivity (~500 S/cm at room temperature) despite localized electrons in Rh3+ and Te6+. Measurable magnetic moments also indicate valence degeneracy between Rh
and the M cation. The measured Seebeck coefficients are relatively low and positive indicating hole-type conduction.