Electron densities in crystals of nonaaqualanthanoid(III) tris(trifluoromethanesulfonates)

Structural Distortion and Chemical Bonding in TlFeO3: Comparison with AFeO3 (A=Rare Earth)

“…It may be related to electronic density around the A cation. Through synchrotron X-ray study for rare earth compounds including La>, Gd>, and Lu> with closed subshell cores, Chatterjee et al (17) indicated that the spherical symmetry of the orbitals for these elements is not preserved when the atoms bind, but the electron cloud is polarized along a speci"c direction. The highly polarized electron density of the A cation was observed in several rare earth orthoferrites, AFeO (A"Y (18), Nd, Dy (19)), which is due to the proximity of the rare earth un"lled d and f states to their "lled states.…”

A synchrotron X-ray study of the electron density in YFeO3

“…The zeroth-order approximation is based on a premise that deformation-density repopulation is dominated by near-degenerate orbitals. Studies of compounds containing rare earths, including La 3+, Gd 3+ and Lu 3+, with closed subsheU cores by Chatterjee, Maslen & Watson (1988), indicate that the spherical symmetry of the prepared state for these elements is not preserved when the atoms bind. In a perturbation expansion treatment of atomic charge density, polarization is ..'.:.:.…”

Electron difference density and structural parameters in CaTiO3

“…The difference density minimizes along the Ti--Ca vectors about 0.55 ,~ from the Ti nucleus, i.e. about 0.05 A further than the distance from the 12g maxima and eg minima to the Ni nucleus in KNiF3, and 0.11 A further than that from the corresponding minima to the Yb nucleus in [Yb(HEO)9](CFaSO3)3 (Chatterjee, Maslen & Watson, 1988). It has been conjectured that such features could be anharmonic and not electronic in origin, because of their proximity to the nuclei and the statistical significance of a high-order cumulant if the corresponding coefficient is determined by least-squares refinement of X-ray diffraction data.…”