Abstract: "Abnormally short interatomic distances are characteristic of aluminum-transition element compounds which occur at the aluminum-rich ends of the phase diagram." Summary: "The theoretical model assumed in this investigation was that of spherical distribution of electrons centered about atomic sites in the V4Al23 structure, represented by the theoretical scattering factors for the isolated atoms. ...It is evident from the (Fo-Fc)-synthesis maps that too much scattering power has been assumed in the immediate vicinity of each atomic site since the negative regions associated with these sties represent electron density differences which are generally two to three times greater than the estimated experimental errors. ...An estimate of the number of electrons associated with the positive regions in the (Fo-Fc)-synthesis maps, and presumably the number of electrons participating in the bonding, could be obtained by computing structure facts with theoretical scattering factors which account for the contributions of the core electrons only. An (Fo-Fc)-synthesis with these Fc values and the Fo values from this investigation should then approximate the actual distribution of the outer electrons."

From abstract: "The mass spectrum of stannane, SnH4, has been studied. Ion fragmentation patterns for both the singly and doubly charged fragments were obtained employing 70-volt electrons. From appearance potential data, an estimation of the bond energies of the tin-hydrogen bond in the ion-species SnH+3-H, SnH+2-H, SnH+-H, Sn+-H has been made along with [delta]Hf for SnH4. The studies were first made with tin of normal isotopic abundance, and then the results were corroborated with SnH4 prepared with the separated isotope 120Sn."