Cation distribution and crystal chemistry of Y3Al5
... discussed the crystal chemistry of silicate garnets on the basis of variations of their interatomic distances and angles, lattice constants etc. They proposed a linear relationship between the lattice constants and the mean cation size on the dodecahedral (eight-coordinate) and the octahedral sites ...
... discussed the crystal chemistry of silicate garnets on the basis of variations of their interatomic distances and angles, lattice constants etc. They proposed a linear relationship between the lattice constants and the mean cation size on the dodecahedral (eight-coordinate) and the octahedral sites ...
Full Text
... In the context of MOMs, the application of crystal engineering,[2] the rational design and assembly of functional crystalline solids, has afforded a large variety of 2D and 3D networks. MBBs most typically consist of metal carboxylate or metal pyridine clusters where the peripheral points of extensi ...
... In the context of MOMs, the application of crystal engineering,[2] the rational design and assembly of functional crystalline solids, has afforded a large variety of 2D and 3D networks. MBBs most typically consist of metal carboxylate or metal pyridine clusters where the peripheral points of extensi ...
NLRP3 inflammasome activation by crystal structures
... endothelium (subendothelial space) [14]. The recruited monocytes differentiate in macrophages and in turn participate to the inflammation by secreting IL-1β. This inflammatory response caused by cholesterol crystals contributes to atheromatous plaque growth that can lead to the rupture of the endoth ...
... endothelium (subendothelial space) [14]. The recruited monocytes differentiate in macrophages and in turn participate to the inflammation by secreting IL-1β. This inflammatory response caused by cholesterol crystals contributes to atheromatous plaque growth that can lead to the rupture of the endoth ...
Luminescence properties of violet-orange
... produces deep color and bright luminescent [10]. Various methods have been reported on the preparation of SrCO3 nanostructures including hydothermal [11] microwaves-assisted [12] microemusion-mediated solvothermal methods [13] solid state reaction [14], co-precipitation method [15] and sol-gel [16]. ...
... produces deep color and bright luminescent [10]. Various methods have been reported on the preparation of SrCO3 nanostructures including hydothermal [11] microwaves-assisted [12] microemusion-mediated solvothermal methods [13] solid state reaction [14], co-precipitation method [15] and sol-gel [16]. ...
Crystal structure of the simian immunodeficiency virus (SIV) gp41
... The analogous deep cavity in the N36 coiled coil of HIV gp41 has been suggested to be a potential drug target (5). Three reasons for this suggestion are: (i) earlier genetic studies indicate that two of the N36 residues that form the cavity (Leu-568 and Trp-571) are critical for membrane-fusion acti ...
... The analogous deep cavity in the N36 coiled coil of HIV gp41 has been suggested to be a potential drug target (5). Three reasons for this suggestion are: (i) earlier genetic studies indicate that two of the N36 residues that form the cavity (Leu-568 and Trp-571) are critical for membrane-fusion acti ...
synthesis and properties of v3+ analogues of jarosite-group
... plumbojarosite and mercury-substituted jarosite (the least stable of all jarosite-type compounds), the M cation is divalent. Consequently, only half of the M sites are filled, and ordering of the cation and vacancies results in a superstructure in which the c axis of the unit cell is doubled (Jambor ...
... plumbojarosite and mercury-substituted jarosite (the least stable of all jarosite-type compounds), the M cation is divalent. Consequently, only half of the M sites are filled, and ordering of the cation and vacancies results in a superstructure in which the c axis of the unit cell is doubled (Jambor ...
Halogen Bonding in Crystal Engineering
... intermolecular forces are directional and strong enough to maintain a certain molecular architecture. Non-covalent interactions such as hydrogen bonds, halogen bonds, ππ interactions, metallophilic interactions, and agostic interactions all have directionality to at least some extent. Especially ...
... intermolecular forces are directional and strong enough to maintain a certain molecular architecture. Non-covalent interactions such as hydrogen bonds, halogen bonds, ππ interactions, metallophilic interactions, and agostic interactions all have directionality to at least some extent. Especially ...
VIKTORIIA LEVUSHKINA Energy transfer processes in the solid
... by the superstructure, which is formed during the synthesis process by transition from the high temperature state to the low temperature state of a solid solution [19]. The high-temperature state is a homogeneous solid solution, in which the substitutional atoms are randomly distributed in the latti ...
... by the superstructure, which is formed during the synthesis process by transition from the high temperature state to the low temperature state of a solid solution [19]. The high-temperature state is a homogeneous solid solution, in which the substitutional atoms are randomly distributed in the latti ...
Crystal Structures, Thermal Analysis, and
... Searching for the optimal method of active pharmaceutical ingredient (API) delivery is an important stage in pharmaceutical drug development. Most APIs are solids under standard conditions and are delivered in tablet form. The efficacy of a drug compound depends on the crystal form of API. There are ...
... Searching for the optimal method of active pharmaceutical ingredient (API) delivery is an important stage in pharmaceutical drug development. Most APIs are solids under standard conditions and are delivered in tablet form. The efficacy of a drug compound depends on the crystal form of API. There are ...
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... This setting for the unit cell was used by Gibbs (1926) for the description of the crystal structure in space group P3121, and it follows that for X-ray and electron diffraction the following intensity relationships exists between positive and negative rhombs: 1011 N 0111, 1012 b 0112, 2011 b 0211, ...
... This setting for the unit cell was used by Gibbs (1926) for the description of the crystal structure in space group P3121, and it follows that for X-ray and electron diffraction the following intensity relationships exists between positive and negative rhombs: 1011 N 0111, 1012 b 0112, 2011 b 0211, ...
Construction of Two Microporous MetalOrganic Frameworks with flu
... to coordinate to metals or metal clusters as nodes or molecular building blocks.25−27 Previous research has shown that the gassorption capacity of a MOF is mainly controlled by its surface area and pore volume.28 For a given framework topology, an effective method to increase its surface area is exte ...
... to coordinate to metals or metal clusters as nodes or molecular building blocks.25−27 Previous research has shown that the gassorption capacity of a MOF is mainly controlled by its surface area and pore volume.28 For a given framework topology, an effective method to increase its surface area is exte ...
Light Scattering of Semiconducting Nanoparticles
... the exciting visible laserlight are about 2.5 eV (corresponding to the wavelength L ≈ 500 nm). Therefore, from Eq. (1) we get S ≈ L and the wavevector in a typical backscat ≈ 4n/L and tering experiment will be on the order of q much smaller than the wavevector q = 2/a at the boundary of the ...
... the exciting visible laserlight are about 2.5 eV (corresponding to the wavelength L ≈ 500 nm). Therefore, from Eq. (1) we get S ≈ L and the wavevector in a typical backscat ≈ 4n/L and tering experiment will be on the order of q much smaller than the wavevector q = 2/a at the boundary of the ...
PDF
... Trivalent metal ions are generally adsorbed on the surface layer, but in a specific study it is seen that trivalent Fe3+ ions occupy the FeO2− site in the form of FeO42− by compensating the charge deficiency via nearby potassium or hydrogen vacancy [9]. Some other groups, like dyes, are also introdu ...
... Trivalent metal ions are generally adsorbed on the surface layer, but in a specific study it is seen that trivalent Fe3+ ions occupy the FeO2− site in the form of FeO42− by compensating the charge deficiency via nearby potassium or hydrogen vacancy [9]. Some other groups, like dyes, are also introdu ...
Freezing and Melting Transitions under Mesoscalic Confinement
... therefore crucial. In the most simple way, this can be done using lattice models, in which the molecules are represented by the lattice sites and the interaction energies between the nearest neighbors are considered to depend on whether a particular site belongs to crystal or liquid. Despite their s ...
... therefore crucial. In the most simple way, this can be done using lattice models, in which the molecules are represented by the lattice sites and the interaction energies between the nearest neighbors are considered to depend on whether a particular site belongs to crystal or liquid. Despite their s ...
Construction of Porous Solids from Hydrogen
... consequently are capable of serving as binding sites to other inclusions. In such an open framework, the selective inclusion of incoming molecular guests is dependent not only on their size and shape but also on their electronic affinity for the metal center. Thus, the process of separating molecule ...
... consequently are capable of serving as binding sites to other inclusions. In such an open framework, the selective inclusion of incoming molecular guests is dependent not only on their size and shape but also on their electronic affinity for the metal center. Thus, the process of separating molecule ...
Interdiffusion in the systems (Nickel(X)-Oxide) - (Cobalt(X)
... 2. When an image on the film is obliterated with a large round black mark, it is an indication that the photographer suspected that the copy may have moved during exposure and thus cause a blurred image. You will find a good image of the page in the adjacent frame. 3. When a map, drawing or chart, e ...
... 2. When an image on the film is obliterated with a large round black mark, it is an indication that the photographer suspected that the copy may have moved during exposure and thus cause a blurred image. You will find a good image of the page in the adjacent frame. 3. When a map, drawing or chart, e ...
Two Novel Bi-Based Borate Photocatalysts: Crystal Structure
... Photocatalysts have attracted much attention for solving the severe problems of energy shortages and environment crises as a potential solution over the past decades.1−3 It is because that they can be used to decompose organic contaminants for environmental purification and split water into hydrogen ...
... Photocatalysts have attracted much attention for solving the severe problems of energy shortages and environment crises as a potential solution over the past decades.1−3 It is because that they can be used to decompose organic contaminants for environmental purification and split water into hydrogen ...
quartz and feldspar microstructures in metamorphic rocks
... porphyroblastesde feldspathpotassiquecontiennentdes inclusions sph6riquesde quartz et de plagioclase,dispos6esal6atoirement ou en train6es qui t6moignent des restesd'un plan de foliation ant6c6dent.Les inclusions de quartz et de feldspath ont tendance d dtre sph6riquesdans les porphyroblastestypique ...
... porphyroblastesde feldspathpotassiquecontiennentdes inclusions sph6riquesde quartz et de plagioclase,dispos6esal6atoirement ou en train6es qui t6moignent des restesd'un plan de foliation ant6c6dent.Les inclusions de quartz et de feldspath ont tendance d dtre sph6riquesdans les porphyroblastestypique ...
Glencoe Earth Science
... Crystals Not all mineral crystals have smooth surfaces and regular shapes like the clear quartz crystals in Figure 2. The rose quartz in the smaller photo of Figure 2 has atoms arranged in repeating patterns, but you can’t see the crystal shape on the outside of the mineral. This is because the rose ...
... Crystals Not all mineral crystals have smooth surfaces and regular shapes like the clear quartz crystals in Figure 2. The rose quartz in the smaller photo of Figure 2 has atoms arranged in repeating patterns, but you can’t see the crystal shape on the outside of the mineral. This is because the rose ...
Microwave Synthesis of Cuprous Oxide Micro
... depend on photo energy and Eg is the band gaps energy. The band gap can be estimated by the intercepts of the tangents to the (αhν)2 vs photon energy (hν) plots. Plots of (αhν)2 vs hν for cuprous oxide samples with different morphologies are shown in Fig. 3(b). The direct band gaps of spherical, str ...
... depend on photo energy and Eg is the band gaps energy. The band gap can be estimated by the intercepts of the tangents to the (αhν)2 vs photon energy (hν) plots. Plots of (αhν)2 vs hν for cuprous oxide samples with different morphologies are shown in Fig. 3(b). The direct band gaps of spherical, str ...
thin film opal photonic crystals - Elpub Wuppertal
... The movement of electrons in semiconductors is well understood and can be controlled and harnessed in electronic devices; this is the basis of modern electronics. The next goal is the replacement of microelectronic components by optical micro-devices. The flow of light is much harder to control and ...
... The movement of electrons in semiconductors is well understood and can be controlled and harnessed in electronic devices; this is the basis of modern electronics. The next goal is the replacement of microelectronic components by optical micro-devices. The flow of light is much harder to control and ...
An introduction to minerals and rocks under the microscope
... This version of the content may include video, images and interactive content that may not be optimised for your device. You can experience this free course as it was originally designed on OpenLearn, the home of free learning from The Open University: http://www.open.edu/openlearn/science-maths-tec ...
... This version of the content may include video, images and interactive content that may not be optimised for your device. You can experience this free course as it was originally designed on OpenLearn, the home of free learning from The Open University: http://www.open.edu/openlearn/science-maths-tec ...
The Crystal Structure of a Fusagenic Sperm Protein Reveals
... HeaVy Atom DeriVatiVes and Data Collection. For lowtemperature data collection, crystals were frozen either in their mother liquor (pH 3 crystal form), or in mother liquor with 20% glycerol (pH 9.5 crystal form). Native data sets were collected for each crystal form at the Stanford Synchrotron Radia ...
... HeaVy Atom DeriVatiVes and Data Collection. For lowtemperature data collection, crystals were frozen either in their mother liquor (pH 3 crystal form), or in mother liquor with 20% glycerol (pH 9.5 crystal form). Native data sets were collected for each crystal form at the Stanford Synchrotron Radia ...
The Extended and Eccentric E-DNA Structure Induced by Cytosine
... © 2000 Nature America Inc. • http://structbio.nature.com ...
... © 2000 Nature America Inc. • http://structbio.nature.com ...
Minerals - Bakersfield College
... arrangement or pattern of atoms that bond together, producing various geometrical configurations that can be observed on several minerals in your box. A mineral’s geometric “shape” is directly due to the internal arrangement of atoms. For example, the mineral pyrite forms cubical structures that ref ...
... arrangement or pattern of atoms that bond together, producing various geometrical configurations that can be observed on several minerals in your box. A mineral’s geometric “shape” is directly due to the internal arrangement of atoms. For example, the mineral pyrite forms cubical structures that ref ...
X-ray crystallography
X-ray crystallography is a tool used for identifying the atomic and molecular structure of a crystal, in which the crystalline atoms cause a beam of incident X-rays to diffract into many specific directions. By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal. From this electron density, the mean positions of the atoms in the crystal can be determined, as well as their chemical bonds, their disorder and various other information.Since many materials can form crystals—such as salts, metals, minerals, semiconductors, as well as various inorganic, organic and biological molecules—X-ray crystallography has been fundamental in the development of many scientific fields. In its first decades of use, this method determined the size of atoms, the lengths and types of chemical bonds, and the atomic-scale differences among various materials, especially minerals and alloys. The method also revealed the structure and function of many biological molecules, including vitamins, drugs, proteins and nucleic acids such as DNA. X-ray crystallography is still the chief method for characterizing the atomic structure of new materials and in discerning materials that appear similar by other experiments. X-ray crystal structures can also account for unusual electronic or elastic properties of a material, shed light on chemical interactions and processes, or serve as the basis for designing pharmaceuticals against diseases.In a single-crystal X-ray diffraction measurement, a crystal is mounted on a goniometer. The goniometer is used to position the crystal at selected orientations. The crystal is bombarded with a finely focused monochromatic beam of X-rays, producing a diffraction pattern of regularly spaced spots known as reflections. The two-dimensional images taken at different rotations are converted into a three-dimensional model of the density of electrons within the crystal using the mathematical method of Fourier transforms, combined with chemical data known for the sample. Poor resolution (fuzziness) or even errors may result if the crystals are too small, or not uniform enough in their internal makeup.X-ray crystallography is related to several other methods for determining atomic structures. Similar diffraction patterns can be produced by scattering electrons or neutrons, which are likewise interpreted by Fourier transformation. If single crystals of sufficient size cannot be obtained, various other X-ray methods can be applied to obtain less detailed information; such methods include fiber diffraction, powder diffraction and (if the sample is not crystallized) small-angle X-ray scattering (SAXS).If the material under investigation is only available in the form of nanocrystalline powders or suffers from poor crystallinity, the methods of electron crystallography can be applied for determining the atomic structure.For all above mentioned X-ray diffraction methods, the scattering is elastic; the scattered X-rays have the same wavelength as the incoming X-ray. By contrast, inelastic X-ray scattering methods are useful in studying excitations of the sample, rather than the distribution of its atoms.