Darstellung und Strukturuntersuchung von Polywolframaten Ein Beitrag zur Aufklärung des Parawolframations A / Preparation and Structure Investigation of Polytungstates A Contribution to the Paratungstate A Problem

1979 ◽  
Vol 34 (3) ◽  
pp. 412-422 ◽  
Author(s):  
Joachim Fuchs ◽  
Ernst-Peter Flindt
Keyword(s):  
Liquid Ammonia ◽  
Sodium Tungstate ◽  
Structure Investigation ◽  
Absorption Bands ◽  
Experimental Conditions ◽  
X Ray ◽  
Predominant Species ◽  
Structure Determinations ◽  
Tungstate Solution ◽  
Ray Methods

Abstract Polytungstates are obtained by the reaction of hydrated tungsten (VI) oxide with bases or salts after occasional addition of organic solvents. With liquid ammonia the as yet unknown ditungstate, (NH4)2W2O7, is produced. Its IR spectrum has few absorption bands suggesting a very simple constitution. Piperidine yields 5 compounds according to varied experimental conditions, which all exhibit approximately paratungstate compositions but different crystal habits, lattice parameters, solubility and IR spectra. Structure determinations indicate that two of these compounds are heptatungstates, the anion of which, W7O246-, has the same structure as the heptamolybdate ion, Mo7O246-. From a comparison of their Raman spectra with the spectrum of a freshly acidified sodium tungstate solution (designated as Paratungstate A) it may be concluded that the heptatungstate ion is the predominant species in such a solution. The anion structure of the previously described tributylammonium(5:24):tungstate [(C4H9)3NH]5H3W12O40 was elucidated by X-ray methods. Here the tungsten atoms show the same arrangement as in the α-dodecatungstatophosphate ion (Keggin structure).

scholarly journals The nature and properties of aluminosilicate framework structures

1934 ◽  
Vol 145 (854) ◽  
pp. 80-103 ◽  
Keyword(s):  
Water Molecules ◽  
Chemical Formula ◽  
Framework Structure ◽  
Experimental Proof ◽  
X Ray ◽  
Structure Determinations ◽  
The Individual ◽  
Related Compounds ◽  
Ray Methods ◽  
Oxygen Atoms

In recent years it has been shown by X-ray methods that the structures of a large number of crystals are based on frameworks of linked tetrahedral groups of oxygen atoms. The individual tetrahedra contain silicon or aluminium atoms, and other atoms (such as sodium or potassium) and water molecules or molecular groups (such as CO 3 and SO 4 ) are located in the interstices of the oxygen atom arrangement. Some of the structure determinations are incomplete and lack direct experimental proof, but in others it has been possible to discover the details of the atomic arrangement. The present writer has been associated with several of these detailed investigations, and in this paper presents some general conclusions which may be drawn from an examination of the available data. Experimental details and evidence for the correctness of individual structures have been published elsewhere. For the purpose of the present paper a framework structure is defined as one in which every tetrahedron SiO 4 or AlO 4 shares all its corners with other tetrahedra, thus accounting for all the silicon aluminium and oxygen atoms in the structure; such a crystal has a chemical formula in which the ratio (Si + Al) to O is 1 to 2. Framework structures include the forms of silica, the felspars, the zeolites, the ultramarines, nepheline and kaliophilite, and related compounds which will be mentioned later; also danburite if boron may be supposed to take the place of aluminium in our definition, and probably leucite.

scholarly journals POSTTRAUMATIC DENSITY OF THE BONE TISSUE OF THE RAT’S MANDIBLE WITHOUT PATHOLOGY, ON THE BACKGROUND OF NALBUPHINE INTAKE AND AFTER LINCOMYCIN TREATMENT

World Science ◽  
2019 ◽  
Vol 2 (11(51)) ◽  
pp. 25-29
Author(s):  
Rostyslav Sohuyko ◽  
Zoryana Masna ◽  
Khrystyna Pavliv
Keyword(s):  
Bone Tissue ◽  
Traumatic Injury ◽  
Experimental Conditions ◽  
X Ray ◽  
Pathological Conditions ◽  
Long Time ◽  
Tissue Reconstruction ◽  
Density Dynamics ◽  
Ray Methods ◽  
Qualitative Changes

Numerous dental manipulations are accompanied by bone injuries. Various types of drug correction are widely used for correction and optimization of bone tissue reconstruction after bone-traumatic injury. The evaluation of the course of reparative osteogenesis becomes possible with the x-ray methods which gives the possibility to evaluate and predict early quantitative and qualitative changes in various pathological conditions, as well as to trace their dynamics in clinical and experimental conditions. In our research we have find out the peculiarities of the density dynamics of the bone tissue of the mandible after causing bone-traumatic injury to intact animals and animals that have been taking nalbuphine for a long time, as well as after treatment with lincomycin.

Neue Tetraaminophosphonium-Salze durch Anionenaustausch in flüssigem Ammoniak

1999 ◽  
Vol 54 (8) ◽  
pp. 1019-1026 ◽  
Author(s):  
Kai Landskron ◽  
Stefan Horstmann ◽  
Wolfgang Schnick
Keyword(s):  
Complex System ◽  
Temperature Gradient ◽  
Hydrogen Bonds ◽  
Single Crystals ◽  
Room Temperature ◽  
Liquid Ammonia ◽  
Acetonitrile Solution ◽  
X Ray ◽  
Cscl Type ◽  
Ray Methods

[P(NH2)4]Br and [P(NH2)4][NO3] have been prepared by anion exchange in liquid ammonia. Single crystals of [P(NH2)4]Br were obtained from an acetonitrile solution in a temperature gradient between 60 °C and room temperature while attempts to grow single crystals of [P(NH2)4][NO3] yielded [P(NH2)4][NO3](OP(NH2)3). Both crystal structures were determined by single crystal X-ray methods at room temperature ([P(NH2)4]Br: P4/nbm, a = 809.2(1), c = 468.1(1) pm, Z = 2, R1 = 0.042, wR2 = 0.077; [P(NH2)4][NO3](OP(NH2)3): Pna21, Z = 4, a = 1023.4(1), b = 1704.7(1), c = 618.0(1) pm, R1 =0.025, wR2 = 0.067. In the solid [P(NH2)4]Br forms a tetragonally distorted variant of the CsCl type of structure. [P(NH2)4][NO3](OP(NH2)3) consists of [P(NH2)4]+cations, [NO3]- anions, and OP(NH2)3 molecules which are interconnected by a complex system of hydrogen bonds.

Die Kristallstrukturen von Ph3PNPh, [Ph3PN(H)Ph][AuI2] und von 2,3-Bis(triphenylphosphoranimino)maleinsäure-N-methylimid / The Crystal Structures of Ph3PNPh, [Ph3PN(H)Ph][AuI2] and of 2,3-Bis(triphenylphosphoranimino)maleic Acid-N-methylimide

1988 ◽  
Vol 43 (2) ◽  
pp. 138-148 ◽  
Author(s):  
Eberhard Böhm ◽  
Kurt Dehnicke ◽  
Johannes Beck ◽  
Wolfgang Hiller ◽  
Joachim Strähle ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Maleic Acid ◽  
Staudinger Reaction ◽  
Space Group ◽  
X Ray ◽  
Bond Angles ◽  
Bond Lengths ◽  
Structure Determinations ◽  
Ray Methods

[Ph3PN(H)Ph][AuI2] (2) is formed by the reaction of AuI with N-Phenyl-iminotriphenylphosphorane, Ph3PNPh in a toluene suspension. 2,3-Bis(triphenylphosphinimino)maleic acid-N-methylimide (3) has been prepared by the Staudinger reaction of 2,3-bis(azido)maleic acid-N-methylimide with PPh3 in THF solution in the form of red crystals. Crystal structure determinations of three iminophosphoranes were carried out by X-ray methods.Ph3PNPh (1): space group P21/c, Z = 4, 2176 independent observed reflexions, R = 0.057. Lattice dimensions (-30 °C): a = 1126.4, b = 1148.6, c = 1476.0 pm; β = 97.21°. The compound forms monomeric molecules with P=N = 160.2 pm and an PNC angle of 130.4°.[Ph3PN(H)Ph][AuI2] (2): space group P1̄, Z = 2, 1780 independent observed reflexions, R = 0.057. Lattice dimensions (18 °C); a = 824.9, b = 1022, c = 1476.2 pm; α = 89.23°, β = 87.41°, γ = 85.65°. The compound consists of ions [Ph3PN(H)Ph]⊕ with P=N = 162.4 pm and PNC = 129.3°, and anions [AuI2]⊖ with Au-I = 261.9 and 259.3 pm, IAuI = 176.8°.(Ph3P)2N2C4O2 (NMe) (3): space group P1̄, Z = 2, 4972 independent observed reflexions, R = 0.050. Lattice dimensions (-90 °C): a = 904.7, b = 993.8, c = 2017.4 pm; α = 101.55°, β = 96.39°, γ = 105.81°. The compound forms monomeric molecules with syn-conformation of the two NPPh3 groups. Bond lengths: P=N = 157.1; 155.3 pm, bond angles: PNC = 133°; 136°

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 548-549 ◽  
Author(s):  
N. J. Zaluzec
Keyword(s):  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
Incident Beam ◽  
Thin Foil ◽  
Experimental Conditions ◽  
X Ray ◽  
Microchemical Analysis ◽  
Analytical Electron ◽  
Image Position ◽  
Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

Synthesis of HTCMgFe for the degradation of indigo carmine through heterogeneous photo-Fenton treatment

MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3273-3282
Author(s):  
I. Cosme-Torres ◽  
M.G. Macedo-Miranda ◽  
S.M. Martinez-Gallegos ◽  
J.C. González-Juárez ◽  
G. Roa-Morales ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Treatment Time ◽  
Uv Light ◽  
Indigo Carmine ◽  
Oh Radicals ◽  
Absorption Bands ◽  
Chromophore Group ◽  
X Ray ◽  
Catalytic Sites ◽  
Scanning Electron

AbstractThe heterogeneous catalyst HTCMgFe was used in the degradation of the IC, through the heterogeneous photo-fenton treatment, this material in combination with H2O2 and UV light degraded the dye in 30 min at pH 3. As the amount of HTCMgFe increases the degradation it was accelerated because there are more active catalytic sites of Fe2+ on the surface of the material, which generates a greater amount of •OH radicals. The HTCMgFe was characterized by infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray energy dispersive elemental analysis (EDS). The UV-vis spectrum shows that the absorption bands belonging to the chromophore group of the IC disappear as the treatment time passes, indicating the degradation of the dye.

Preparation, properties and structure of some intermediate nido- and arachno-monocarbaboranes

1981 ◽  
Vol 46 (10) ◽  
pp. 2345-2353 ◽  
Author(s):  
Karel Baše ◽  
Bohumil Štíbr ◽  
Jiří Dolanský ◽  
Josef Duben
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Nmr Spectra ◽  
Liquid Ammonia ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Starting Compound

The 6-N(CH3)3-6-CB9H11 carbaborane reacts with sodium in liquid ammonia with the formation of 6-CB9H12- which was used as a starting compound for preparing the 4-CB8H14, 9-L-6-CB9H13 (L = (CH3)2S, CH3CN and P(C6H5)3), 1-(η5-C5H5)-1,2-FeCB9H10-, and 2,3-(η5-C5H5)2-2,31-Co2CB9H10- carboranes. The 4-CB8H14 compound was dehydrogenated at 623 K to give 4-(7)-CB8H12 carborane. Base degradation of 6-N(CH3)3-6-CB9H11 in methanol resulted in the formation of 3,4-μ-N(CH3)3CH-B5H10. The structure of all compounds was proposed on the basis of their 11B and 1H NMR spectra and X-ray diffraction was used in the case of the transition metal complexes.

scholarly journals Zeolite NaP1 Functionalization for the Sorption of Metal Complexes with Biodegradable N-(1,2-dicarboxyethyl)-D,L-aspartic Acid

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2518
Author(s):  
Dorota Kołodyńska ◽  
Yongming Ju ◽  
Małgorzata Franus ◽  
Wojciech Franus
Keyword(s):  
Experimental Data ◽  
Aspartic Acid ◽  
Ph Value ◽  
Complexing Agents ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Modified Zeolite ◽  
X Ray ◽  
Slow Release Fertilizers ◽  
Pseudo Second Order

The possibility of application of chitosan-modified zeolite as sorbent for Cu(II), Zn(II), Mn(II), and Fe(III) ions and their mixtures in the presence of N-(1,2-dicarboxyethyl)-D,L-aspartic acid, IDHA) under different experimental conditions were investigated. Chitosan-modified zeolite belongs to the group of biodegradable complexing agents used in fertilizer production. NaP1CS as a carrier forms a barrier to the spontaneous release of the fertilizer into soil. The obtained materials were characterized by Fourier transform infrared spectroscopy (FTIR); surface area determination (ASAP); scanning electron microscopy (SEM-EDS); X-ray fluorescence (XRF); X-ray diffraction (XRD); and carbon, hydrogen, and nitrogen (CHN), as well as thermogravimetric (TGA) methods. The concentrations of Cu(II), Zn(II), Mn(II), and Fe(III) complexes with IDHA varied from 5–20 mg/dm3 for Cu(II), 10–40 mg/dm3 for Fe(III), 20–80 mg/dm3 for Mn(II), and 10–40 mg/dm3 for Zn(II), respectively; pH value (3–6), time (1–120 min), and temperature (293–333 K) on the sorption efficiency were tested. The Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin adsorption models were applied to describe experimental data. The pH 5 proved to be appropriate for adsorption. The pseudo-second order and Langmuir models were consistent with the experimental data. The thermodynamic parameters indicate that adsorption is spontaneous and endothermic. The highest desorption percentage was achieved using the HCl solution, therefore, proving that method can be used to design slow-release fertilizers.

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