Bi2/3Ce1/3Rh2O5: A new mixed-valent Rh oxide with hitherto unknown structure

The new compound Bi2/3Ce1/3Rh2O5 has been discovered. It is currently the only known compound in the Bi–Ce–Rh–O system, and it crystallizes in a previously unknown structure type. The structure was established from single crystal X-ray diffraction data. Interatomic distances indicate the oxidation states as Bi2/33+Ce1/34+Rh23.33+O5. The structure indicates no ordering between Rh3+ and Rh4+. The lack of charge ordering is consistent with the metallic properties determined from electrical conductivity, Seebeck coefficient, and magnetic susceptibility measurements.