A stable germanone as the first isolated heavy ketone with a terminal oxygen atom

2012 ◽  
Vol 4 (5) ◽  
pp. 361-365 ◽  
Author(s):  
Liangchun Li ◽  
Tomohide Fukawa ◽  
Tsukasa Matsuo ◽  
Daisuke Hashizume ◽  
Hiroyuki Fueno ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Terminal Oxygen Atom

Oxofluoro-oxalato-vanadate des vierwertigen Vanadins: Schwingungsspektrum und Struktur von Na3[VOF(C2O4)2] • 6 H2O.

1976 ◽  
Vol 31 (5) ◽  
pp. 537-540 ◽  
Author(s):  
Helmut Rieskamp ◽  
Rainer Mattes
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Fluorine Atom ◽  
Direct Methods ◽  
Terminal Oxygen Atom ◽  
Triclinic Space Group ◽  
Trans Effect ◽  
Space Group ◽  
X Ray ◽  
In Cis

The Na and NH4 salts of the [VOF(C2O4)2]3--ion have been prepared. The crystal structure of the former has been determined from X-ray diffractometer data. The crystals are triclinic, space group P with Z = 2. The structure was solved by `direct methods' and refined to R 0.050 for 1749 reflections. In the anion, vanadium(IV) is octahedrally coordinated by a terminal oxygen atom, a fluorine atom in cis-position to the former, and two bidentate oxalate ligands. The terminal V—O-bond exhibits a strong ‘trans’ effect.

Density Functional Theory Study of TinO2n-m Clusters (n=1-4, m=0,1)

2012 ◽  
Vol 507 ◽  
pp. 79-82
Author(s):  
Dong Mei Li ◽  
Zhi Hua Xiong ◽  
Qi Xin Wan
Keyword(s):  
Density Functional Theory ◽  
Oxygen Atom ◽  
Density Functional ◽  
Energy Levels ◽  
Binding Energies ◽  
Terminal Oxygen Atom ◽  
Functional Theory ◽  
Energy Gaps ◽  
Equilibrium Geometries ◽  
Oxygen Atoms

Using density functional theory, the equilibrium geometries of TinO2n and TinO2n-1 clusters (n=1-4) have been obtained. It suggests that the structures of these two corresponding clusters are changed slightly, except for the number of terminal oxygen atoms. The electronic properties have also been investigated. The bond between Ti and terminal oxygen atom is found to be more covalent than other Ti-O bonds. It also indicates that by deleting one terminal oxygen atom, HOMO is mainly derived from titanium atoms with least coordination, but not from singly-coordination oxygen atoms as that in the stoichiometric clusters. Highest energy levels of least-coordination Ti atoms shift highly and they become more reactive. In addition, HOMO-LUMO energy gaps and binding energies were observed. The calculated results show that the energy gaps decrease quickly, except for Ti4O7 clusters and all the binding energies are relatively large.

Fluorreiche Oxofluorovanadate(V): Die Kristallstruktur von [enH2][VOF5]. / Fluorine-Rich Oxofluorovanadates(V): Crystal Structure of [enH2][VOF5]

1976 ◽  
Vol 31 (11) ◽  
pp. 1453-1455 ◽  
Author(s):  
Helmut Rieskamp ◽  
Rainer Mattes
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Fluorine Atom ◽  
Terminal Oxygen Atom ◽  
X Ray

The crystal structure of triclinic [enH2][VOF5], prepared in aqueous solution, has been determined from X-ray diffractometer data (R = 0.076 for 527 reflections). The structure contains monomeric [VOF5]2--ions. The bond distances are 1.54(1) Å (terminal oxygen), 1.80(1) (average for the cis-fluorine atoms) and 2.10(1) Å for the fluorine atom in transposition to the terminal oxygen atom. This fluorine atom is involved in strong hydrogen bonds originating from the [NH3CH2CH2NH3]2+ cation with cisoid conformation. Earlier results about the existence of K2VOF5 could not be confirmed

A study of twinning in YBa2Cu3O7−x by large-angle convergent-beam electron diffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 20-21
Author(s):  
P.A. Midgley ◽  
R. Vincent ◽  
D. Cherns
Keyword(s):  
Electron Diffraction ◽  
Oxygen Atom ◽  
Strain Field ◽  
Large Angle ◽  
Convergent Beam Electron Diffraction ◽  
Orthorhombic Distortion ◽  
Beam Electron ◽  
Resultant Powder ◽  
Convergent Beam ◽  
Mesh Grid

The oxygenation of YBa2Cu3O7−x (YBCO) leads to an orthorhombic distortion of the unit cell to accommodate the extra oxygen atom. This makes the formation of twins energetically favourable with CuO4 planar unit chains running alternately along the a and b axes of the parent tetragonal structure. The geometry of this twinning is such that four possible twin variants may co-exist with the twin boundaries lying in the (110) or (110) planes of the deformed structure. The traces of these planes are not mutually perpendicular and thus the crystal is strained to allow for the mismatch. It is to the nature of this strain field that this work has been addressed.Sintered samples were prepared by crushing and dispersing the resultant powder onto a very fine Cu mesh grid. Single crystals were chemically thinned to perforation. No discernible artefacts were seen and similar results were obtained with either method.

Fast oxygen atom facility for studies related to low earth orbit activities

1992 ◽  
Author(s):  
G. CALEDONIA ◽  
R. KRECH ◽  
B. UPSCHULTE ◽  
D. SONNENFROH ◽  
D. OAKES ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Low Earth Orbit ◽  
Earth Orbit

Theoretical Studies of High Energy Oxygen Atom Chemistry

2004 ◽  
Author(s):  
M. Braunstein ◽  
J. Duff ◽  
R. Shroll ◽  
L. Bernstein ◽  
S. Adler-Golden
Keyword(s):  
Oxygen Atom ◽  
High Energy ◽  
Theoretical Studies ◽  
Atom Chemistry

Conformation and electronic structure of aromatic chloroformates

1987 ◽  
Vol 52 (4) ◽  
pp. 970-979 ◽  
Author(s):  
Otto Exner ◽  
Pavel Fiedler
Keyword(s):  
Electronic Structure ◽  
Oxygen Atom ◽  
Strong Interaction ◽  
Electron Distribution ◽  
Room Temperature ◽  
Functional Group ◽  
Dipole Moments ◽  
Carbonyl Oxygen ◽  
Nonpolar Solvents ◽  
Single Method

Aromatic chloroformates Ib-Ie were shown to exist in the ap conformation, in agreement with aliphatic chloroformates, i.e. the alkyl group is situated cis to the carbonyl oxygen atom as it is the case in all esters. While 4-nitrophenyl chloroformate (Ie) is in this conformation in crystal, in solution at most several tenths of percent of the sp conformation may be populated at room temperature and in nonpolar solvents only. A new analysis of dipole moments explained the previous puzzling results and demonstrated the impossibility to determine the conformation by this single method, in consequence of the strong interaction of adjoining bonds. If, however, the ap conformation is once proven, the dipole moments reveal some features of the electron distribution on the functional group, characterized by the enhanced polarity of the C-Cl bond and reduced polarity of the C=O bond. This is in agreement with the observed bond lengths and angles.

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