The electron density in beryllium intermetallic compounds

Abstract

The electron deformation density of Li(,2)BeF(,4) was investigated with respect to a description of purely covalent bonding. X-ray diffraction data was collected from a single Li(,2)BeF(,4) crystal in the range 0.0 sin (theta)/(lamda) (LESSTHEQ) 1.20(ANGSTROM)('-1). The expected Be-F covalent bonding interaction was found; however, no support was found for covalent bonding between Li and F. An electron deformation density study was done based on the x-ray diffraction data for CaBe(,13). There is clear evidence of multicenter bonding within the polyhedral array of beryllium atoms. No evidence was found for the participation of calcium in a pattern of directed bonding. X-ray diffraction data was collected for the intermetallic compound MoBe(,12) in the range 0 < sin (theta)/(lamda) (LESSTHEQ) 1.25(ANGSTROM)('-1). The electron deformation density showed multicenter bonding in the polyhedral array of beryllium atoms. Also, in evidence was directed bonding involving the Mo atom. The structure of a compound containing rhenium and beryllium was determined. The face centered cubic structure has only partial occupancy at the rhenium positions and is formulated as Re(,0.92)Be(,16).