Zur Kristallchemie der Wasserstoff–Sauerstoff-Bindungen

1994 ◽  
Vol 209 (1) ◽  
Author(s):  
H. Alig ◽  
J. Lösel ◽  
M. Trömel
Keyword(s):  
Coordination Number ◽  
Inorganic Compounds ◽  
Close Correlation ◽  
Coordination Numbers ◽  
High Coordination

AbstractThe interdependence of hydrogen – oxygen distances in inorganic compounds can be described by a close correlation if sufficiently high coordination numbers for hydrogen are taken into account. For this purpose, the coordination is favourably defined as chemical coordination number

Wechselwirkungen in Molekülkristallen, 156 [1, 2]. Kristallzüchtung und Strukturbestimmung von (Imidodiphosphat)-Alkalisalzen mit Kationen niedriger und hoher Koordinationszahlen / Interaction in Molecular Crystals, 156 [1, 2]. Crystal Growth and Structure Determination of Alkali(imidodiphosphate) Salts with Cations of Low and High Coordination Numbers

2000 ◽  
Vol 55 (9) ◽  
pp. 773-784 ◽  
Author(s):  
Hans Bock ◽  
Erik Heigel ◽  
Norbert Nagel
Keyword(s):  
Crystal Growth ◽  
Coordination Number ◽  
Molecular Crystals ◽  
Chelating Ligands ◽  
Chain Polymer ◽  
Coordination Numbers ◽  
Structural Differences ◽  
A Chain ◽  
High Coordination

Imidodiphosphates ⊖N[PO(OR)2]2 and Imidodiphosphonates ⊖N[POR2]2 are effective chelating ligands for a variety of metal cations including even Na⊕, for which a lipophilically wrapped hexameric polyion cluster has been structurally characterized. The corresponding hexameric lithium and polyrubidium ion complexes reported here exhibit considerable structural differences: The rather small Li⊕ cations of coordination number five and tetraphenylimidodiphosphate form an isolated hexameric aggregate analogous to the Na⊕ one, whereas the larger Rb⊕ with coordination number seven and (3,4-dimethylphenyl)substituents crystallizes as a chain polymer. Based on the crystal structures, the dominant Coulomb attractions between cations and anions, the spatial requirement of the ligands and the essential phenyl/phenyl interactions in their lipophilic skin are discussed

scholarly journals Robin Jon Hawes Clark. 16 February 1935—6 December 2018

2020 ◽  
Vol 68 ◽  
pp. 103-129
Author(s):  
Alwyn G. Davies ◽  
Paul F. McMillan
Keyword(s):  
Raman Spectroscopy ◽  
Inorganic Compounds ◽  
Resonance Raman Spectroscopy ◽  
Linear Chain ◽  
Mixed Valence ◽  
Far Infrared ◽  
Vanadium Complexes ◽  
Coordination Numbers ◽  
Metal Metal ◽  
High Coordination

Robin Clark was a distinguished physical/inorganic chemist who made major discoveries in the coordination chemistry of the early transition metals, especially of titanium and vanadium complexes with high coordination numbers (notably seven and eight) and of the structures and physical properties of mixed valence, linear chain and metal–metal bonded compounds. He applied far-infrared spectroscopy to study metal–ligand vibrations systematically and established the technique for structure elucidation of transition metal and main group compounds. He also developed Raman and resonance Raman spectroscopy applied to inorganic compounds and highly coloured solids including mineral samples. That work led to his seminal applications of microbeam Raman spectroscopy for the identification of pigments and other constituents of artworks and historical artefacts, thereby developing a basis for testing their provenance and the identification of forgeries.

An X-ray and Neutron Scattering Study of the Structure of Zinc Vanadate Glasses

2001 ◽  
Vol 56 (6-7) ◽  
pp. 478-488
Author(s):  
Uwe Hoppe ◽  
Rainer Kranold ◽  
Emil Gattef ◽  
Jörg Neuefeind ◽  
David A. Keen
Keyword(s):  
Neutron Diffraction ◽  
Coordination Number ◽  
Short Range ◽  
Short Range Order ◽  
X Ray ◽  
Coordination Numbers ◽  
Gaussian Functions ◽  
Scattering Study ◽  
Neutron Scattering Study ◽  
Vanadate Glasses

Abstract The short-range order of vitreous V20 5 and of three (Zn0)Jt(V20 5)1_x glasses with x = 0.2, 0.4, and 0.5 is studied by X-ray and neutron diffraction experiments where the change of the contrast allows to resolve the V -0 and Z n -0 correlations. The V -0 and the Z n -0 first-neighbor peaks are approximat­ ed by several Gaussian functions. In case of vitreous V20 5 two obvious V -0 distances exist which are related with V 0 4 and V 0 5 units. With ZnO additions the V -O coordination number decreases from 4.4 in vitreous V20 5 to 4.0 in the metavanadate glass where the strongest decrease of the fraction of V 0 5 units is found for glasses of * < 0.2. Dominantly, the V 0 5 groups are linked with the neighboring units by comers. The Z n-0 coordination numbers of the modified glasses are about five with closest dis­ tances of = 0.200 nm.

The first coordination number for liquid metals

2004 ◽  
Vol 82 (4) ◽  
pp. 291-301 ◽  
Author(s):  
J R Cahoon
Keyword(s):  
Distribution Function ◽  
Radial Distribution Function ◽  
Coordination Number ◽  
Liquid Metals ◽  
Liquid Density ◽  
Isotropic Liquid ◽  
Coordination Numbers ◽  
Solid Structure ◽  
Atomic Diameter ◽  
Liquid Element

A simple and absolute method for the calculation of the first coordination number for any pure, isotropic liquid element is presented. The liquid density and the position for the first peak of the radial distribution function, assumed to be the atomic diameter, are the only parameters required. The coordination number for liquid metals that exhibit a BCC (body-centred cube) solid structure averages 7.4 while the first coordination number for liquid metals with a FCC (face-centred cube) or CPH (close-packed hexagonal) solid structure averages 7.1. Those liquid elements that have less closed-packed solid structures have a first coordination number less than 7.0. The calculation also correctly predicts the first coordination number for liquid Se to be 2.4, consistent with its chain-like structure. The calculated values for the liquid element coordination numbers are consistent with the decrease in density of a few percent that occurs upon melting and appear to be related to the Engel–Brewer valence of the solid, which suggests that the electron structure of the solid may be retained upon melting. The first coordination numbers for liquid Ge and Si were calculated to be 5.0 and 4.7, respectively, larger than the value of 4.0 for solid structures. The increase in coordination number upon melting accounts for the increase in density of Ge and Si that occurs upon melting.PACS No.: 61.20.Gy

scholarly journals Coordination Numbers of Bivalent Ions in Organic Solvents

2021 ◽  
Vol 95 (10) ◽  
pp. 2059-2064
Author(s):  
M. A. Orekhov
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Molecular Dynamic ◽  
Coordination Number ◽  
Organic Solvents ◽  
Organic Molecule ◽  
Dynamic Models ◽  
Coordination Numbers ◽  
A Value ◽  
Bivalent Ions

Abstract Molecular dynamic models are created for properties of bivalent ions in organic solvents. It is shown that molecules of the considered solvents bound to ions via oxygen atoms. A theoretical model is developed that describes the ion coordination number. The coordination number in this model is determined by the ratio between the sizes of the ion and the atom organic molecule bound to it. It is shown that the coordination number depends weakly on the solvent and strongly on the type of ion. A value of 0.13 nm is obtained for the effective size of an oxygen atom bound to a bivalent ion. The constructed theoretical model agrees with the results from molecular dynamic calculations and the available experimental data.

Structure and stereochemistry in 'f-block' complexes of high coordination number. VII. The [M(unidentate X)2(unidentate Y)6] system: Crystal structure of hexaaquadichloroeuropium(III) chloride (a redetermination)

1983 ◽  
Vol 36 (3) ◽  
pp. 477 ◽  
Author(s):  
DL Kepert ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Coordination Number ◽  
Title Compound ◽  
Chlorine Atoms ◽  
Coordination Environment ◽  
Twofold Axis ◽  
High Coordination Number ◽  
Europium Atom ◽  
High Coordination

The crystal structure of the title compound [EuCl2(OH2)2]Cl ('europium trichloride hexahydrate') has been redetermined from single-crystal diffractometer data at 295 K and refined to a residual of 0.040 for 1094 independent 'observed' reflections. Crystals are monoclinic, P2/n, a 9.659(3), b 6.529(2), c 7.936(4) �, β 93.67(4)�, Z 2. The europium atom lies on a crystallographic twofold axis, which passes between the two planes of a square-antiprismatic coordination environment in which the two chlorine atoms, on opposite faces, lie cis to each other. Eu-O distances range from 2.401(6) to 2.431(5) �; Eu-Cl is 2.774(2) �.

Fluorescent phenoxy benzoxazole complexes of zirconium and hafnium: synthesis, structure and photo-physical behaviour

2018 ◽  
Vol 47 (32) ◽  
pp. 11245-11252 ◽  
Author(s):  
Lisa Kuhlmann ◽  
Rafael Methling ◽  
Jasmin Simon ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
...  
Keyword(s):  
Coordination Numbers ◽  
Physical Behaviour ◽  
Blue Region ◽  
High Coordination

Ten new Zr(iv) and Hf(iv) complexes with phenoxy-benzoxazole ligands with high coordination numbers up to eight show ligand-centered fluorescence with emission maxima in the blue region.

Sign in / Sign up

Export Citation Format

Share Document