The crystal and molecular structure of ammonium titanyl oxalate

Ammonium titanyl oxalate monohydrate, (NH4)2 TiO(C2O4)2·H2O, is monoclinic with cell parameters A = 13.473(2), B = 11.329(1), C = 17.646(2) Å, β = 126.66(1)°. The space group is P21/c with Z = 8, dc = 1.808 g cm−3 and dm = 1.80 g cm−3. The crystal structure was determined from single-crystal diffractometer data and refined by least-squares methods using isotropic thermal parameters. The conventional R factor was 7.0% for 2466 used reflections.\ud The anions consist of cyclic tetranuclear complexes [TiO O (C2O4)2]48− with symmetry. The titanium atoms are six-coordinated with two bridging oxygen atoms cis to one another and four oxygen atoms of bidentate oxalate groups, together forming a distorted octahedron. The titanium atoms of the tetramer are linked through oxygen atoms at two neighbouring apices of each octahedron. The actual name of the compound should therefore be: ammonium cyclotetra-di-μ-oxo-cis-dioxalatotitanate(IV)tetrahydrate.\ud The di-μ-oxo-tetratitanium unit is an eight-membered ---O---Ti---O--- ring with Ti-O distances of successively 1.840(7), 1.785(7) and 1.855(6), 1.788(8) Å, repeated by the centre of symmetry, and the orientation of the atoms suggests the presence of dπ---pπ 3-center 2-electron bonds in each Ti---O---Ti set.\ud The Ti---O distances trans to the bridging oxygen atoms are much longer: 2.060(7), 2.101(7), 2.081(7) and 2.116(7) Å respectively, as is to be expected from the charge displacement due to the dπ---pπ bonding. Most O---Ti---O angles in the distorted octahedra differ considerably from 90°.\ud As was found by difference Fourier synthesis and thermal analysis, half of the crystal water is held very loosely compared to the other half

Leadership in a post-merger context: The importance of people skills over politics

Drawing on the merger and CEO succession literature as well as on findings from research on organizational change, this study examines what leadership issues drive success in a post-merger context. Our data from 45 recently merged units within a cooperative bank in Europe indicate that the people skills of the newly appointed top manager matter most. Specifically, his/her integration ability followed by the ability to positively influence the internal working environment are significantly correlated with post-merger success. Politics in terms of whether the top manager had a track record inside or outside the organization did not appear to be important.management and organization theory ;

Clinical prediction models to inform individualized decision-making in subfertile couples : a stratified medicine approach

Funding This work was supported by a Chief Scientist Office Postdoctoral Training Fellowship in Health Services Research and Health of the Public Research (Ref PDF/12/06). The views expressed in this paper represent the views of the authors and not necessarily the views of the funding body.Peer reviewedPostprin

Taking the Plunge: Requiring the ETD

It made sense for Caltech, the California Institute of Technology (a private, technically focused, U.S. university, http://www.caltech.edu), to go electronic when it comes to theses. It took, however, more than three years: From March 1999 when Prof. Ed Fox of the Virginia Technical University spoke at Caltech to July 2002 when ETDs became required for all PhD candidates. How was it done and what are the lessons learned

Mach's Principle and Model for a Broken Symmetric Theory of Gravity

We investigate spontaneous symmetry breaking in a conformally invariant gravitational model. In particular, we use a conformally invariant scalar tensor theory as the vacuum sector of a gravitational model to examine the idea that gravitational coupling may be the result of a spontaneous symmetry breaking. In this model matter is taken to be coupled with a metric which is different but conformally related to the metric appearing explicitly in the vacuum sector. We show that after the spontaneous symmetry breaking the resulting theory is consistent with Mach's principle in the sense that inertial masses of particles have variable configurations in a cosmological context. Moreover, our analysis allows to construct a mechanism in which the resulting large vacuum energy density relaxes during evolution of the universe.Comment: 9 pages, no figure