Synthesis, characterization, electrical and magnetic properties of CrTa2O6 and CrNb2O6

Abstract Compounds CrTa 2 O 6 and CrNb 2 O 6 were synthesized. The former presents a slightly distorted trirutile structure and the latter has a tetragonal structure. Both are semiconducting oxides with an activation energy of 0.5 eV. Magnetism measurements are in good agreement with Cr 2+ in CrTa 2 O 6 , contrary to CrNb 2 O 6 , which contains Cr 3+ corresponding to a charge transfer between Cr 2+ and Nb 5+ . At the present time, CrTa 2 O 6 remains the only oxide with divalent chromium.