Our X-ray diffraction data index to a P m 3m structure (Fig. ) with a cell parameter of a 0 = (3.8076 ± 0.0001) Å, consistent with the value of a 0 = (3.798 ± 0.005) Å reported by Vorres and Donohue . This result corresponds to a ReO 3 -type structural model, com-