The structural study of Sr4Fe6O13using a Weissenberg technique and synchrotron radiation – unusual ionic radii of five-coordinated Fe3+ions

The structure of Sr4Fe6O13is orthorhombic, space groupIba2, with unit cell dimensionsa= 11.278(3) Å,b= 18.953(6) Å,c= 5.546(3) Å,Z= 4. The crystal structure was refined by full-matrix leastsquares toR= 0.010 using 301 reflections measured with an imaging plate using a Weissenberg camera and mono-chromatized synchrotron radiation of wavelength 1.000 Å. The result is essentially the same with the previously reported structure (Yoshiasa, Ueno, Kanamaru, Horiuchi, 1986) but has yielded some details of the structure in which Fe–O bondings are involved. The polyhedral distortions and ionic radii for the five coordinated Fe3+ions in the structure have been discussed in comparison with those of related structures.