Fig. 3. (a) X-ray diffraction pattern of the long synthesis sample (see text for details). The theoretical peak positions for cubic (Powder Diffraction File 00-012-0797 from ICDD), hexagonal (04-016-2410) and monoclinic (00-042-1465) crystal structures are displayed. (b) Diffraction pattern obtained by radial averaging of the selected area electron diffraction (SAED) shown in (d). The selected area corresponds to image (c). (e) HRTEM image of a particle in the monoclinic phase and (f) the associated fast Fourier transform.