Abstract
The atomic scattering factor and the electron distribution were studied by X-ray diffractometry in order to know the electronic state of oxygen in crystalline Cu2O. The intensity measurements were performed within an experimental error of about 1 to 3%. The atomic scattering factor of oxygen was determined referring to the scattering factor of copper, and was compared with theoretical values of O2−, O and O2+. The observed value corresponds best to the scattering factor of O2−. However, a small deviation from the ideally ionic O2− state, for example the state of O1.85−, is possible, which may be expected from the positive hole model for Cu2O crystal. The electron distribution in some special planes of the unit cell of the crystal was determined by three dimensional Fourier synthesis. The electron distributions were found to be almost spherical around each atom except the overlapping of the electron cloud in the region between neighbouring Cu and O atoms.
