X-ray Measurement of the Scattering Factor of Iron in Ordered Fe₃Al

X-ray measurements on the absolute integrated intensities of several superlattice reflections on an ordered Fe 3 Al single crystal were made to obtain an estimate of the number of localized 3 d electrons in iron. The experiments were made with Mo K α radiation with a thin single crystal cut for transmission geometry, so as to avoid surface roughness effects. Extinction effects, minimized by restricting the measurements to the comparatively weak superlattice reflections, were estimated from a wavelength analysis of the integrated intensities. Finally, neutron analysis was used for obtaining a knowledge of the state of atomic ordering in the particular sample and for establishing the temperature factors of the iron and aluminum atoms. Calculations of the iron scattering factor from the final results show it to be in substantial agreement with that of the free iron atom (6 3 d electrons). This is in agreement with the conclusions of Batterman 2),3) and contrasts with the low number of 3 d electrons given by Weiss and DeMarco 1) .