Aluminiumphosphate mit nichtzentrosymmetrischen Schicht-und Raumnetzstrukturen aus topologisch verwandten Motiven: 1. KAl2(PO4)2(OH)·4H2O/Aluminum Phosphates with Non-Centrosym metric Layer-and Framework-Structures of Topologically Related Motifs 1. KAl2(PO4)2(OH)·4H2O

1997 ◽  
Vol 52 (12) ◽  
pp. 1439-1446 ◽  
Author(s):  
Stefan Dick ◽  
Gisbert Großmann ◽  
Gisela Ohms ◽  
Thomas Zeiske
Keyword(s):  
Nmr Spectra ◽  
Potassium Phosphate ◽  
Water Molecules ◽  
Phosphate Solution ◽  
Orthorhombic Space Group ◽  
Adjacent Layer ◽  
Oh Groups ◽  
Isotropic Line ◽  
Aluminum Phosphates ◽  
Phosphate Groups

Abstract KAl2(PO4)2(OH)·4H2O could be obtained by the reaction of gibbsite with a potassium-phosphate solution of pH = 5.5 at 333 K. A single crystal X-ray structure analysis showed that KAl2(PO4)2(OH)·4H2O is isotypic with the mineral minyulite. Crystal data: orthorhombic space group Pba2, a = 934.7(1), b = 982, 1 (1), c = 551,0(1) pm, Z = 2. It possesses dimeric units of Al-octahedra which are bridged by an OH-and two bidentate phosphate groups. The dimers are linked by phosphate to plane polar layers. Cavities in the layers are occupied by K ions. One corner of each phosphate tetrahedron is not connected to Al but accepts four hydrogen bonds from water molecules bound to Al of the adjacent layer. A powder neutron scattering experiment with KAl2(PO4)2(OD)·4D2O showed that four D atoms and P coordinate the hydrogen bond accepting O in KAl2(PO4)2(OD)·4D2O like a square pyramid. Analogous dimeric building units are found in the Al phosphate minerals minyulite and morinite; similar dimers of Fe octahedra occur in the mineral copiapite, a number of Fe containing enzymes and numerous synthetic iron complexes.High-resolution 31P solid-state NMR spectra show only one isotropic line at δiso = -9.6 ppm and confirm the presence of one symmetry independent phosphorus site in the unit cell. In the 1H-MAS-NMR spectra the water molecules and the bridging OH groups show signals at 5.4 and 1.4 ppm, respectively

Aluminiumphosphate mit nichtzentrosymmetrischen Schicht- und Raumnetzstrukturen aus topologisch verwandten Motiven: 2. KAl2(PO4)2(OH)·2H2O/Aluminum Phosphates with Non-Centrosymmetric Layer- and Framework-Structures of Topologically Related Motifs: 2. KAl2(PO4)2(OH)·2H2O

1997 ◽  
Vol 52 (12) ◽  
pp. 1447-1455 ◽  
Author(s):  
Stefan Dick ◽  
Gisbert Großmann ◽  
Gisela Ohms ◽  
Manfred Müller
Keyword(s):  
Nmr Spectra ◽  
Three Dimensional ◽  
Potassium Phosphate ◽  
Mas Nmr ◽  
Water Molecules ◽  
Phosphate Solution ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Aluminum Phosphates ◽  
Phosphate Groups

Abstract KAl2(PO4)2(OH)·2H2O was obtained by the reaction of gibbsite with a potassium-phosphate solution of pH = 5.5 at 373 K. A single crystal X-ray structure analysis showed that it is an ordered, F-free K-analog of the microporous compound AIPO4-CI2 . Crystal data: orthorhombic space group P212121, a = 920.5(1), b = 970.7(2), c = 982.8(2) pm, Z = 4. The structure consists of dimeric units of AIO6 octahedra and AIO5 trigonal bipyramids, bridged by an OH and two bidentate phosphate groups. The dimers are linked by phosphate to form corrugated layers which are topologically related to the layers in KAl2(PO4)2(OH)·4H2O and minyulite. The layers are connected by Al-O-P and hydrogen bonds to a three dimensional framework structure with K ions in channel-like cavities. A neutron powder scattering experiment with KAl2(PO4)2(OD)·2D2O showed that the bridging OD group and only one D of each water molecule are involved in hydrogen bonding.31P MAS NMR spectra show two isotropic lines at δiso = -6.9 and -18,7 ppm of the intensity ratio 1:1 and confirm the presence of two crystallographically independent P atoms in the unit cell. In the 1H MAS NMR spectra the water molecules and the bridging OH group show signals at 5.9 and 1.1 ppm, respectively.

Über die Struktur von synthetischem Tinsleyit K[Al2(PO4)2 (OH)(H2O)]·H2O/The Structure of Synthetic Tinsleyite K[Al2(PO4)2(OH)(H2O )]·H2O

1999 ◽  
Vol 54 (11) ◽  
pp. 1385-1390 ◽  
Author(s):  
Stefan Dick
Keyword(s):  
Three Dimensional ◽  
Potassium Phosphate ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
Phosphate Solution ◽  
Thermal Loss ◽  
Crystal Data ◽  
Framework Structure ◽  
X Ray ◽  
Phosphate Ions

Synthetic tinsleyite K[Al2(PO4)2(OH)(H2O)]·H2O has been obtained by the reaction of gibbsite with a potassium-phosphate solution of pH = 7 at 423 K within five days. A single crystal X-ray structure analysis has shown that synthetic tinsleyite is isotypic with the mineral leucophosphite K[Fe2(PO4 )2(OH)(H2O )]·H2O. Crystal data: monoclinic space group P21/n,a = 949.9(2), b = 950.3(2), c = 953,5(2) pm, β = 103,26(3)°, Z = 4. The structure of tinsleyite consists of tetranuclear A I4O2 units formed by a central pair of edge sharing AlO6 octahedra, to which two additional AlO6 octahedra are attached sharing corners. These units are crosslinked by phosphate ions to a three dimensional framework structure with tunnels along [010], occupied by potassium cations. While one type of water molecules is attached to Al, a second type is fixed in the structure by hydrogen bonds only. As a consequence two steps for thermal loss of water at 341 K and 471 K are observed.

Komplexe mit substituierten 2,5-Dihydroxy-p-benzochinonen: Das isotype Paar BaC6X2O4 · 3 H2O (X = Cl, Br) / Complexes with Substituted 2,5-Dihydroxy-p-benzochinones: The Isotypic Pair BaC6X2O4 · 3 H2O (X = Cl, Br)

1986 ◽  
Vol 41 (12) ◽  
pp. 1495-1500 ◽  
Author(s):  
Christian Robl ◽  
Armin Weiss
Keyword(s):  
Water Molecule ◽  
Water Molecules ◽  
Topochemical Reaction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Oxygen Atoms

AbstractBaC6X2O4 · 3H2O (X = Cl, Br) crystallizes in the orthorhombic space group Cmca. 4 of the 8 oxygen atoms around Ba2+ belong to two different dianions, chelating Ba2+. In this way 1-dimensional corrugated chains are formed, interlinked by two oxygen atoms of neighbouring chains, thus forming layers. This interconnection is of polar character within a layer. The in­terlinking oxygen atoms have one carbon- and two Ba2+ neighbours. CN 8 is completed by two water molecules. The latter and a further water molecule situated between the layers may be removed reversibly in a topochemical reaction without destruction of the structure.

scholarly journals Chemical-Vapor-Deposited Graphene as Charge Storage Layer in Flash Memory Device

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
W. J. Liu ◽  
L. Chen ◽  
P. Zhou ◽  
Q. Q. Sun ◽  
H. L. Lu ◽  
...  
Keyword(s):  
Flash Memory ◽  
Room Temperature ◽  
Metal Layer ◽  
Chemical Vapor ◽  
Charge Trapping ◽  
Memory Device ◽  
Water Molecules ◽  
Oh Groups ◽  
Chemical Vapor Deposited ◽  
A Charge

We demonstrated a flash memory device with chemical-vapor-deposited graphene as a charge trapping layer. It was found that the average RMS roughness of block oxide on graphene storage layer can be significantly reduced from 5.9 nm to 0.5 nm by inserting a seed metal layer, which was verified by AFM measurements. The memory window is 5.6 V for a dual sweep of ±12 V at room temperature. Moreover, a reduced hysteresis at the low temperature was observed, indicative of water molecules or −OH groups between graphene and dielectric playing an important role in memory windows.

scholarly journals Fluorescence Properties and Synthesis of Green-Emitting Tb3+-Activated Amorphous Calcium Silicate Phosphor by Ultraviolet Irradiation of 378 nm

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Yoshiyuki Kojima ◽  
Masaaki Numazawa ◽  
Shinnosuke Kamei ◽  
Nobuyuki Nishimiya
Keyword(s):  
Ultraviolet Irradiation ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Atomic Ratio ◽  
Emission Wavelength ◽  
Excitation Wavelength ◽  
Water Molecules ◽  
Oh Groups ◽  
Ultraviolet Excitation ◽  
Silicate Phosphor

The excitation wavelength of conventional Tb3+-activated phosphor is near 270 nm. This study describes novel green-emitting Tb3+-activated amorphous calcium silicate by ultraviolet excitation at 378 nm. The Tb3+-activated amorphous calcium silicate was prepared by heating a sample of Tb3+-activated calcium silicate hydrate (CSH) at 900°C for 30 minutes. The emission wavelength of the resulting phosphor was 544 nm. The optimum excitation wavelength within the range 300–400 nm was 378 nm. The Tb3+-activated amorphous calcium silicate emitted green by ultraviolet irradiation. The optimum initial Tb/Ca atomic ratio of this phosphor was about 0.5. A mechanism for the action of the phosphor is proposed, in which Tb3+ions existing in the layer of the CSH lead to loss of water molecules and OH groups.

2H and 195 Pt NMR Studies of Molecular and Electron Spin Dynamics in Paramagnetic [Cu(H2O)6][PtCl 6]

1998 ◽  
Vol 53 (6-7) ◽  
pp. 447-452
Author(s):  
Takahiro Iijima ◽  
Kengo Orii ◽  
Motohiro Mizuno ◽  
Masahiko Suhara
Keyword(s):  
Activation Energy ◽  
Electron Spin ◽  
Nmr Spectra ◽  
Chemical Shift Anisotropy ◽  
Spin Lattice Relaxation ◽  
Water Molecules ◽  
Temperature Phase ◽  
Nmr Studies ◽  
Teller Distortion ◽  
Exponential Factor

Abstract The temperature dependences of 2H and 195Pt NMR spectra and the spin-lattice relaxation time T1 were measured for [Cu(H2O)6][PtCl6]. From the simulation of 2H NMR spectra, the jump rate of 180° flips of the water molecules (k), the nuclear quadrupole interaction parameters (e2Qq/h, ƞ) and the electron-nucleon dipolar interaction parameter (vD) were obtained. By measuring 2H T1, k was estimated in the temperature range where the spectrum is insensitive to the motion of the water molecules. Above the phase transition temperature, the pre-exponential factor k0 = 8 x1011 s-1 and the activation energy Ea = 15 kJmol-1 for 180° flips of the water molecules were obtained from the spectral simulation and T1. 195Pt NMR spectra showed an axially symmetric and unsymmetric powder pattern of the chemical shift anisotropy at the high and low temperature phase, respectively. For the deuterated compound, the correlation times of the electron spin in Cu2+ were estimated from 195Pt T1 and the activation energy for jumping between the different configurations of Jahn-Teller distortion Δ = 200 K was obtained.

Functionalizingλ-AlOOH Surface with Silanol -- an Ab-initio Study

2007 ◽  
Vol 1000 ◽  
Author(s):  
Petri Lehtinen ◽  
Guido Grundmeier ◽  
Alexander Blumenau
Keyword(s):  
Ab Initio ◽  
Adsorption Process ◽  
Water Environment ◽  
Water Molecules ◽  
Organic Film ◽  
Oh Groups ◽  
Inorganic Films ◽  
Adsorption Of Water ◽  
Zinc Coatings ◽  
Insight Into

AbstractOn HDG-steel, zinc coatings are used for corrosion protection. Part of that coating is composed of aluminum and this leads to the creation of aluminum oxide film on the coating with thicknesses of 2-3 nanometers. This layer is an amorphous boehmite film.Boehmite, or λ-AlOOH, has several application areas, but for us the interesting ones are related to an area where the surface is functionalized, for example in a way that the organic and inorganic films can be “glued” together. A good candidate for the interface is the silanol molecule. The idea is that the OH-groups of the molecule attach on the inorganic film and the methyl groups on the organic film and hence promote adhesion between the two.We present theoretical ab-initio results of adsorption of water and silanol molecules on the λ AlOOH (0001)-surface. Since the experimental adsorption of the silanol on the boehmite surface is done in water environment, the adsorption process is therefore a competing process. We will present some result of adsorption of silanol in the presence of water molecules to get an insight into this process.

Spectroscopic studies of vanadium biosorption on different types of carbohydrate biomass

2013 ◽  
Vol 91 (3) ◽  
pp. 186-195 ◽  
Author(s):  
Jousy García ◽  
Juan Carlos González ◽  
María Inés Frascaroli ◽  
Silvia García ◽  
Patricia Blanes ◽  
...  
Keyword(s):  
Metal Ion ◽  
Orange Peel ◽  
Spectroscopic Studies ◽  
Visible Range ◽  
Water Molecules ◽  
Main Process ◽  
Paramagnetic Resonance ◽  
Oh Groups ◽  
Surface Level ◽  
Different Types

The biosorption potential of different types of carbohydrate biomass is investigated to evaluate their application to purify water contaminated by vanadium in environmentally relevant oxidation states (VIV and VV). Spectroscopic studies were done by electron paramagnetic resonance (EPR), vanadium nuclear magnetic resonance (51V NMR), circular dichroism (CD), and electronic absorption in the visible range (vis). Both d-galacturonic and d-glucuronic acids are major components of plant cellular wall polysaccharides. The interaction of VIV with the model ligands d-galacturonic and d-glucuronic acids showed that complexation starts at low pH values (pH 3) and that carboxylate and sugar–OH groups, as well as water molecules, are involved in the coordination. At pH > 4.5, coordination promotes the sugar–OH deprotonation and new species form with the ligand chelating the metal ion via oxygen atoms of carboxylate and of adjacent sugar–O− donors. The studies with pectin and citric acid show the ability of both compounds to partially reduce VV to VIV in solution and the EPR parameters suggest coordination of carboxylate, sugar–OH, and water molecules. The interaction of VV with biomass from different sources shows that grapefruit, orange peel, and plane tree fruit are the most suitable candidates for the biosorption of vanadium. Studies with VV and grapefruit (or the grainless stalk of corn) indicate that the reduction takes place at the “surface” of the solid. EPR studies on the interaction of VIV with different carbohydrate biomass show their ability to complex high amounts of VIV. We propose that the biosorption mechanism, when the biomass is in contact with VV species, involves sorption, reduction, and retention at the surface level of VIV coordinated by oxygen donors of the biomass. When the interaction starts with VIV, the main process just involves the uptake of the metal ion at the surface level.

Darstellung, 11B-, 13C-NMR- und Schwingungsspektren von Cs2[B6H5(p-C6H4(NO2))] und Cs2[B6H5(C6H3-l-(CH3)-5-(NO2))] sowie Kristallstruktur von (CH2Py2)[B6Cl5(p-C6H4(NO2))]·CH3CN / Preparation, 11B , 13C-NMR and Vibrational Spectra of Cs2[B6H5(p-C6H4(NO2))], Cs2[B6H5 (C6H3-1 -(CH3 )-5-(NO2))] and Crystal Structure of (CH2Py2)[B6Cl5(p-C6H4(NO2))]·CH3CN

2000 ◽  
Vol 55 (11) ◽  
pp. 1031-1036
Author(s):  
S. Zander ◽  
W. Preetz
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Deae Cellulose ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Derivatives Of ◽  
Ir And Raman

The first aryl derivatives of c/oso-hexahydrohexaborate are formed by reaction of [B6H6]2- with 1-bromo-4-nitrobenzene and 2-bromo-5-nitrotoluene in acetonitrile at 80 °C. Cs2[B6H5- (1,4-C6H4(NO2))] and Cs2[B6H5(C6H3-1-(CH3)-5-(NO2))] can be isolated by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. Further treatment with /V-chlorosuccinimide yields the perhalogenated derivative (CH2Py2)[B6Cl5(1,4-Ph(NO2))]CH3CN which has been characterized by X-ray diffraction analysis (orthorhombic, space group P2( 2,2t, a = 9.810(4), b - 14.412(3), c - 18.586(9) A, Z = 4). The 11B NMR spectra of all compounds are consistent with a monosubstituted B6-cluster. The IR and Raman spectra exhibit characteristic BB, BH, CH, CC and NO vibrations, respectively.

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