1990 年 32 巻 3 号 p. 175-183
The Maximum Entropy Method to obtain Electron Density Distribution Map (EDDM) of crystals is outlined. In the method, the particular attention is paid to treat the powder diffraction data. By using the method, three-dimensional EDDM of silicon is drawn from the 30 structure fact ors determined accurately by Saka and Kato [T.Saka & N.Kato: Acta Cryst. A42, 468 (1986) ] . The EDDM of CeO2 obtained from powder data is also shown. It is found that the EDDM drawn by the MEM can reveal details of electron density distribution in solid state such as chemical bonding and electrons in vacant sites.