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:Direct methods in crystallography are a collection of mathematical techniques that seek to determine crystal structure based on measurements of diffraction patterns and potentially other a priori knowledge (constraints). The central challenge of inverting measured diffraction intensities (i.e. applying an inverse Four... | 1 | Crystallography |
*[http://www-ssrl.slac.stanford.edu/absorb.html The SSRL Absorption Package] —
*[https://web.archive.org/web/20081223025616/http://www.gwyndafevans.co.uk/chooch.html CHOOCH] —
*[https://web.archive.org/web/20090909133542/http://www.hwi.buffalo.edu/snb/ Shake-and-Bake] (SnB) —
*[http://shelx.uni-ac.... | 1 | Crystallography |
To a known volume of sample, an excess but known amount of I is added, which the oxidizing agent then oxidizes to I. I dissolves in the iodide-containing solution to give triiodide ions (I), which have a dark brown color. The triiodide ion solution is then titrated against standard thiosulfate solution to give iodide ... | 0 | Chromatography + Titration + pH indicators |
The main use of litmus is to test whether a solution is acidic or basic, as blue litmus paper turns red under acidic conditions, and red litmus paper turns blue under basic or alkaline conditions, with the color change occurring over the pH range 4.5–8.3 at . Neutral litmus paper is purple. Wet litmus paper can also b... | 0 | Chromatography + Titration + pH indicators |
In any form of chromatography, the rate at which the solute moves down the column is a direct reflection of the percentage of time the solute spends in the mobile phase. To achieve separation in either elution or displacement chromatography, there must be appreciable differences in the affinity of the respective solut... | 0 | Chromatography + Titration + pH indicators |
Unit cell parameters (a,b,c,α,β,γ) can be computed from the final relaxed positions of the ions. In a NaCl calculation, the final position of the Na ion might be (0,0,0) in picometer Cartesian coordinates and the final position of the Cl ion might be (282,282,282). From this, we see that the lattice constant would be... | 1 | Crystallography |
The majority of systems utilize two two-cylinder piston pumps, one for each buffer, combining the output of both in a mixing chamber. Some simpler systems use a single peristaltic pump which draws both buffers from separate reservoirs through a proportioning valve and mixing chamber. In either case the system allows th... | 0 | Chromatography + Titration + pH indicators |
Eriochrome Black T is a complexometric indicator that is used in complexometric titrations, e.g. in the water hardness determination process. It is an azo dye. Eriochrome is a trademark of Huntsman Petrochemical, LLC.
In its deprotonated form, Eriochrome Black T is blue. It turns red when it forms a complex with calciu... | 0 | Chromatography + Titration + pH indicators |
Specifically, an SMB system has two or more identical columns, which are connected to the mobile phase pump, and each other, by a multi-port valve. The plumbing is configured in such a way that:
:a) all columns will be connected in series, forming a single continuous loop;
:b) typically, between each column there will ... | 0 | Chromatography + Titration + pH indicators |
The leuco form of malachite green was first prepared by Hermann Fischer in 1877 by condensing benzaldehyde and dimethylaniline in the molecular ratio 1:2 in the presence of sulfuric acid. | 0 | Chromatography + Titration + pH indicators |
Medical use of HPLC typically use mass spectrometer (MS) as the detector, so the technique is called LC-MS or LC-MS/MS for tandem MS, where two types of MS are operated sequentially. When the HPLC instrument is connected to more than one detector, it is called a hyphenated LC system. Pharmaceutical applications are th... | 0 | Chromatography + Titration + pH indicators |
Another example is hematite on magnetite . The magnetite structure is based on close-packed oxygen anions stacked in an ABC-ABC sequence. In this packing the close-packed layers are parallel to (111) (a plane that symmetrically "cuts off" a corner of a cube). The hematite structure is based on close-packed oxygen anio... | 1 | Crystallography |
In geometric phase analysis, crystallographic quantities are not determined at one particular point of the input image. Instead, they are quantified across the whole image resulting in a two-dimensional map of given quantity. Quantities which can be mapped with geometric phase analysis include interplanar distances (d-... | 1 | Crystallography |
The special cases of 2D (wallpaper groups) and 3D (space groups) are most heavily used in applications, and they can be treated together. | 1 | Crystallography |
For an infinite two-dimensional lattice, defined by its primitive vectors , its reciprocal lattice can be determined by generating its two reciprocal primitive vectors, through the following formulae,
where is an integer and
Here represents a 90 degree rotation matrix, i.e. a quarter turn. The anti-clockwise rotation... | 1 | Crystallography |
More accurately, a single formula that describes the titration of a weak acid with a strong base from start to finish is given below:
where
" φ = fraction of completion of the titration (φ < 1 is before the equivalence point, φ = 1 is the equivalence point, and φ > 1 is after the equivalence point)
: = the concentrati... | 0 | Chromatography + Titration + pH indicators |
The chemical character of azo violet may be attributed to its azo group (-N=N-), six-membered rings, and hydroxyl side groups. Due to steric repulsions, azo violet is most stable in the trans-configuration, but isomerization of azo dyes by irradiation is not uncommon. The para-position tautomerization of azo violet pro... | 0 | Chromatography + Titration + pH indicators |
After being scattered by the sample, the profile of the diffracted beam needs to be detected by a two-dimensionally resolving X-ray detector. The classical "detector" is X-ray sensitive film, with nuclear plates as a traditional alternative. The first step beyond these "offline" detectors were the so-called image plate... | 1 | Crystallography |
The shape of a powder diffraction reflection is influenced by the characteristics of the beam, the experimental
arrangement, and the sample size and shape. In the case of monochromatic neutron sources the convolution
of the various effects has been found to result in a reflex almost exactly Gaussian in shape. If this
d... | 1 | Crystallography |
Bromophenol is also used as a colour marker to monitor the process of agarose gel electrophoresis and polyacrylamide gel electrophoresis. Since bromophenol blue carries a slight negative charge at moderate pH, it will migrate in the same direction as DNA or protein in a gel; the rate at which it migrates varies accord... | 0 | Chromatography + Titration + pH indicators |
Conductometry is a measurement of electrolytic conductivity to monitor a progress of chemical reaction. Conductometry has notable application in analytical chemistry, where conductometric titration is a standard technique. In usual analytical chemistry practice, the term conductometry is used as a synonym of conductom... | 0 | Chromatography + Titration + pH indicators |
The liquid chromatograph is complex and has sophisticated and delicate technology. In order to properly operate the system, there should be a minimum basis for understanding of how the device performs the data processing to avoid incorrect data and distorted results.
HPLC is distinguished from traditional ("low pressur... | 0 | Chromatography + Titration + pH indicators |
The defining property of a crystal is its inherent symmetry. Performing certain symmetry operations on the crystal lattice leaves it unchanged. All crystals have translational symmetry in three directions, but some have other symmetry elements as well. For example, rotating the crystal 180° about a certain axis may res... | 1 | Crystallography |
Cryo crystallography enables X-ray data collection at cryogenic temperatures, typically 100 K.
*Crystals are transferred from the solution they have grown in (called mother liquor) to a solution with a cryo-protectant to prevent ice formation.
*Crystals are mounted in a glass fiber (as opposed to a capillary.)
*Crystal... | 1 | Crystallography |
The absorption of methyl orange on the UV/vis spectrum is between 350-550 nm, with its peak at 464 nm. This is in the green-purple visible light range and explains why methyl orange is, in fact, orange. | 0 | Chromatography + Titration + pH indicators |
For any 2-dimensional lattice, the unit cells are parallelograms, which in special cases may have orthogonal angles, equal lengths, or both. Four of the five two-dimensional Bravais lattices are represented using conventional primitive cells, as shown below.
The centered rectangular lattice also has a primitive cell ... | 1 | Crystallography |
TLE uses continuous-wave lasers (typically with a wavelength of around 1000 nm) located outside the vacuum chamber to heat sources of material in order to generate a flux of vapor via evaporation or sublimation. Owing to the localized nature of the heat induced by the laser, a portion of the source may be transformed i... | 1 | Crystallography |
Reflections, or mirror isometries, can be combined to produce any isometry. Thus isometries are an example of a reflection group. | 1 | Crystallography |
* F. Geiss (1987): Fundamentals of thin layer chromatography planar chromatography, Heidelberg, Hüthig,
* Justus G. Kirchner (1978): Thin-layer chromatography, 2nd edition, Wiley
* Joseph Sherma, Bernard Fried (1991): Handbook of Thin-Layer Chromatography (= Chromatographic Science. Bd. 55). Marcel Dekker, New York N... | 0 | Chromatography + Titration + pH indicators |
Put simply, ion suppression describes the adverse effect on detector response due to reduced ionisation efficiency for analyte(s) of interest, resulting from the presence of species in the sample matrix which compete for ionisation, or inhibit efficient ionisation in other ways. Use of MS/MS as a means of detection may... | 0 | Chromatography + Titration + pH indicators |
As an abstract graph, the Laves graph can be constructed as the maximal abelian covering graph of the complete graph . Being an abelian covering graph of means that the vertices of the Laves graph can be four-colored such that each vertex has neighbors of the other three colors and so that there are color-preserving s... | 1 | Crystallography |
Prior to HPLC, scientists used benchtop column liquid chromatographic techniques. Liquid chromatographic systems were largely inefficient due to the flow rate of solvents being dependent on gravity. Separations took many hours, and sometimes days to complete. Gas chromatography (GC) at the time was more powerful than l... | 0 | Chromatography + Titration + pH indicators |
Friedel's salt is a layered double hydroxide (LDH) of general formula:
or more explicitly for a positively-charged LDH mineral:
or by directly incorporating water molecules into the Ca,Al hydroxide layer:
where chloride and hydroxide anions occupy the interlayer to compensate the excess of positive charges.
In the ce... | 1 | Crystallography |
The history and evolution of reversed phase stationary phases in described in detail in an article by Majors, Dolan, Carr and Snyder.
In the 1970s, most liquid chromatography runs were performed using solid particles as the stationary phases, made of unmodified silica gel or alumina. This type of technique is now refe... | 0 | Chromatography + Titration + pH indicators |
A widely used coordinate system is the Cartesian coordinate system, which consists of orthonormal basis vectors. This means that,
and
However, when describing objects with crystalline or periodic structure a Cartesian coordinate system is often not the most useful as it does not often reflect the symmetry of the latt... | 1 | Crystallography |
GC–MS is increasingly used for detection of illegal narcotics, and may eventually supplant drug-sniffing dogs. A simple and selective GC–MS method for detecting marijuana usage was recently developed by the Robert Koch Institute in Germany. It involves identifying an acid metabolite of tetrahydrocannabinol (THC), the a... | 0 | Chromatography + Titration + pH indicators |
In chromatography, the retardation factor, R, is the fraction of the sample in the mobile phase at equilibrium, defined as: | 0 | Chromatography + Titration + pH indicators |
The Zener ratio is a dimensionless number that is used to quantify the anisotropy for cubic crystals. It is sometimes referred as anisotropy ratio and is named after Clarence Zener. Conceptually, it quantifies how far a material is from being isotropic (where the value of 1 means an isotropic material).
Its mathematica... | 1 | Crystallography |
Chromatography is a common technique used in the field of Forensic Science. Chromatography is a method of separating the components of a mixture from a mobile phase. Chromatography is an essential tool used in forensic science, helping analysts identify and compare trace amounts of samples including ignitable liquids, ... | 0 | Chromatography + Titration + pH indicators |
In a mirror furnace, material is heated by the lamps whose radiation is focused by mirrors. They are widely used for growing single crystals for scientific purposes, using the "floating zone" method. | 1 | Crystallography |
There are just 230 different ways of arranging objects in regular three-dimensional arrays. In molecular crystallography, these arrangements are called space groups. However, only 65 of these arrangements are accessible to chiral objects or chiral molecules. The remaining 165 space groups contain either a center of sym... | 1 | Crystallography |
Between 1936 and 1940, Japanese chemist and lichenologist Yasuhiko Asahina published a series of papers in the Journal of Japanese Botany detailing the microcrystallization technique. This simple and rapid method allowed for the identification of major metabolites in hundreds of lichen species, contributing significant... | 1 | Crystallography |
The dopped stone is ground at precise angles and indexes on cutting laps of progressively finer grit, and then the process is repeated a final time to polish each facet. Accurate repetition of angles in the cutting and polishing process is aided by the angle readout and index gear. The physical process of polishing is ... | 1 | Crystallography |
A relatively new topography-related technique (first published in 1996) is the so-called reticulography. Based on white-beam topography, the new aspect consists in placing a fine-scaled metallic grid ("reticule") between sample and detector. The metallic grid lines are highly absorbing, producing dark lines in the reco... | 1 | Crystallography |
A circular filter paper is taken and the sample is deposited at the center of the paper. After drying the spot, the filter paper is tied horizontally on a Petri dish containing solvent, so that the wick of the paper is dipped in the solvent. The solvent rises through the wick and the components are separated into conce... | 0 | Chromatography + Titration + pH indicators |
The contact graph of an arbitrary finite packing of unit balls is the graph whose vertices correspond to the packing elements and whose two vertices are connected by an edge if the corresponding two packing elements touch each other. The cardinality of the edge set of the contact graph gives the number of touching pair... | 1 | Crystallography |
Different methods to determine the endpoint include:
*Indicator: A substance that changes color in response to a chemical change. An acid–base indicator (e.g., phenolphthalein) changes color depending on the pH. Redox indicators are also used. A drop of indicator solution is added to the titration at the beginning; the... | 0 | Chromatography + Titration + pH indicators |
*[http://www.isallaboutmath.com/proof.aspx Proof about Stereographic Projection taking circles in the sphere to circles in the plane] | 1 | Crystallography |
Sulfites and hydrogensulfites reduce iodine readily in acidic medium to iodide. Thus when a diluted but excess amount of standard iodine solution is added to known volume of sample, the sulfurous acid and sulfites present reduces iodine quantitatively:
(This application is used for iodimetry titration because here Iodi... | 0 | Chromatography + Titration + pH indicators |
Alizarine Yellow R is a yellow colored azo dye made by the diazo coupling reaction. It is usually commercially available as a sodium salt. In its pure form, it is a rust-colored solid. It is mainly used as a pH indicator. | 0 | Chromatography + Titration + pH indicators |
An epitaxial layer can be doped during deposition by adding impurities to the source gas, such as arsine, phosphine, or diborane. Dopants in the source gas, liberated by evaporation or wet etching of the surface, may also diffuse into the epitaxial layer and cause autodoping. The concentration of impurity in the gas ph... | 1 | Crystallography |
There are a number of common formats for performing gel filtration for smaller (less than 4mL) volumes:
* Chromatography columns
* Gravity-flow columns
* Chromatography cartridges
* Centrifuge columns
* Centrifuge plates
Gravity-flow, or drip, columns use head-pressure from a buffer-chase to push the sample through the... | 0 | Chromatography + Titration + pH indicators |
:Diffraction patterns collected through PED often agree well-enough with the kinematical pattern to serve as input data for direct methods calculations. A three-dimensional set of intensities mapped over the reciprocal lattice can be generated by collecting diffraction patterns over multiple zone axes. Applying direct ... | 1 | Crystallography |
Modification had also been extended past hydrophobic and hydrophilic attachments, charged compounds have also been introduced to TRPs. Kobayashi et al. had previously performed successful modifications to separate bioactive ionic compounds, and continued on that success to improve separation efficiency of bioactive com... | 0 | Chromatography + Titration + pH indicators |
Some forensic techniques, believed to be scientifically sound at the time they were used, have turned out later to have much less scientific merit or none. Some such techniques include:
* Comparative bullet-lead analysis was used by the FBI for over four decades, starting with the John F. Kennedy assassination in 1963.... | 0 | Chromatography + Titration + pH indicators |
Numerous niche applications exploit the intense color of MG. It is used as a biological stain for microscopic analysis of cell biology and tissue samples. In the Gimenez staining method, basic fuchsin stains bacteria red or magenta, and malachite green is used as a blue-green counterstain. Malachite green is also used ... | 0 | Chromatography + Titration + pH indicators |
Crystal violet is one of the components of methyl violet, a dye first synthesized by Charles Lauth in 1861. From 1866, methyl violet was manufactured by the Saint-Denis-based firm of Poirrier et Chappat and marketed under the name "Violet de Paris". It was a mixture of the tetra-, penta- and hexamethylated pararosanili... | 0 | Chromatography + Titration + pH indicators |
White-beam topography uses the full bandwidth of X-ray wavelengths in the incoming beam, without any wavelength filtering (no monochromator). The technique is particularly useful in combination with synchrotron radiation sources, due to their wide and continuous wavelength spectrum. In contrast to the monochromatic cas... | 1 | Crystallography |
A rule-of-thumb is that any molecule that will dissolve in methanol or a less polar solvent is compatible with SFC, including non-volatile polar solutes. CO has polarity similar to n-heptane at its critical point. The solvent's elution strength can be increased just by increasing density or alternatively, using a pola... | 0 | Chromatography + Titration + pH indicators |
Perovskites may be structured in layers, with the structure separated by thin sheets of intrusive material. Different forms of intrusions, based on the chemical makeup of the intrusion, are defined as:
* Aurivillius phase: the intruding layer is composed of a [] ion, occurring every n layers, leading to an overall ch... | 1 | Crystallography |
To image time-dependent, periodically fluctuating phenomena, topography can be combined with stroboscopic exposure techniques. In this way, one selected phase of a sinusoidally varying movement is selectively images as a "snapshot". First applications were in the field of surface acoustic waves on semiconductor surface... | 1 | Crystallography |
These groups may contain only two-fold axes, mirror planes, and/or an inversion center. These are the crystallographic point groups 1 and (triclinic crystal system), 2, m, and (monoclinic), and 222, , and mm2 (orthorhombic). (The short form of is mmm.) If the symbol contains three positions, then they denote symmetr... | 1 | Crystallography |
Chromatofocusing is a protein-separation technique that allows resolution of single proteins and other ampholytes from a complex mixture according to differences in their isoelectric point. Chromatofocusing uses ion exchange resins and is typically performed on fast protein liquid chromatography (FPLC) or similar equip... | 0 | Chromatography + Titration + pH indicators |
Ballistics is "the science of the motion of projectiles in flight". In forensic science, analysts examine the patterns left on bullets and cartridge casings after being ejected from a weapon. When fired, a bullet is left with indentations and markings that are unique to the barrel and firing pin of the firearm that eje... | 0 | Chromatography + Titration + pH indicators |
Researchers in structural geology are concerned with the orientations of planes and lines for a number of reasons. The foliation of a rock is a planar feature that often contains a linear feature called lineation. Similarly, a fault plane is a planar feature that may contain linear features such as slickensides.
These ... | 1 | Crystallography |
Diamonds cubic structure is in the Fdm space group (space group 227), which follows the face-centered cubic Bravais lattice. The lattice describes the repeat pattern; for diamond cubic crystals this lattice is "decorated" with a motif of two tetrahedrally bonded atoms in each primitive cell, separated by of the width ... | 1 | Crystallography |
As an acid–base indicator, its useful range lies between pH 3.0 and 4.6. It changes from yellow at pH 3.0 to blue at pH 4.6; this reaction is reversible. Bromophenol blue is structurally related to phenolphthalein (a popular indicator). | 0 | Chromatography + Titration + pH indicators |
SMB provides lower production cost by requiring less column volume, less chromatographic separation media ("packing" or "stationary phase"), using less solvent and less energy, and requiring far less labor.
At industrial scale an SMB chromatographic separator is operated continuously, requiring less resin and less solv... | 0 | Chromatography + Titration + pH indicators |
A type of ion exchange chromatography, membrane exchange is a relatively new method of purification designed to overcome limitations of using columns packed with beads. Membrane Chromatographic devices are cheap to mass-produce and disposable unlike other chromatography devices that require maintenance and time to reva... | 0 | Chromatography + Titration + pH indicators |
Matrix-assisted inlet ionization (MAII) has shown that the laser is not necessary for the ionization process. Ions are formed when matrix-analyte is introduced to the vacuum of a mass spectrometer through an inlet aperture. LSI is a subset of MAII and is now called laserspray inlet ionization (LSII). Laser spray inlet... | 0 | Chromatography + Titration + pH indicators |
In physics, a Bragg plane is a plane in reciprocal space which bisects a reciprocal lattice vector, , at right angles. The Bragg plane is defined as part of the Von Laue condition for diffraction peaks in x-ray diffraction crystallography.
Considering the adjacent diagram, the arriving x-ray plane wave is defined by:
W... | 1 | Crystallography |
Crystals can be classified in three ways: lattice systems, crystal systems and crystal families. The various classifications are often confused: in particular the trigonal crystal system is often confused with the rhombohedral lattice system, and the term "crystal system" is sometimes used to mean "lattice system" or ... | 1 | Crystallography |
The van Deemter equation in chromatography, named for Jan van Deemter, relates the variance per unit length of a separation column to the linear mobile phase velocity by considering physical, kinetic, and thermodynamic properties of a separation. These properties include pathways within the column, diffusion (axial and... | 0 | Chromatography + Titration + pH indicators |
* First position – primary direction – z direction, assigned to the higher-order axis.
* Second position – symmetrically equivalent secondary directions, which are perpendicular to the z-axis. These can be 2, m, or
* Third position – symmetrically equivalent tertiary directions, passing between secondary directions.... | 1 | Crystallography |
The phenolic metabolic pathways and enzymes may be studied by mean of transgenesis of genes. The Arabidopsis regulatory gene in the production of anthocyanin pigment 1 (AtPAP1) may be expressed in other plant species. | 0 | Chromatography + Titration + pH indicators |
Liquid-phase epitaxy (LPE) is a method to grow semiconductor crystal layers from the melt on solid substrates. This happens at temperatures well below the melting point of the deposited semiconductor. The semiconductor is dissolved in the melt of another material. At conditions that are close to the equilibrium between... | 1 | Crystallography |
LaAlO doped with neodymium gave laser emission at 1080 nm. Mixed methylammonium lead halide () cells fashioned into optically pumped vertical-cavity surface-emitting lasers (VCSELs) convert visible pump light to near-IR laser light with a 70% efficiency. | 1 | Crystallography |
Using matrix matched calibration standards can compensate for ion suppression. Using this technique, calibration standards are prepared in identical sample matrix to that used for analysis (e.g. plasma) by spiking a normal sample with known concentrations of analyte. This is not always possible for biological samples, ... | 0 | Chromatography + Titration + pH indicators |
Crystal chemistry is the study of the principles of chemistry behind crystals and their use in describing structure-property relations in solids, as well as the chemical properties of periodic structures. The principles that govern the assembly of crystal and glass structures are described, models of many of the techno... | 1 | Crystallography |
Kapustinskii originally proposed the following simpler form, which he faulted as "associated with antiquated concepts of the character of repulsion forces".
Here, K. This form of the Kapustinskii equation may be derived as an approximation of the Born–Landé equation, below.
Kapustinskii replaced r, the measured dista... | 1 | Crystallography |
Twenty of the 32 crystal classes are piezoelectric, and crystals belonging to one of these classes (point groups) display piezoelectricity. All piezoelectric classes lack inversion symmetry. Any material develops a dielectric polarization when an electric field is applied, but a substance that has such a natural charge... | 1 | Crystallography |
Titration (also known as titrimetry and volumetric analysis) is a common laboratory method of quantitative chemical analysis to determine the concentration of an identified analyte (a substance to be analyzed). A reagent, termed the titrant or titrator, is prepared as a standard solution of known concentration and volu... | 0 | Chromatography + Titration + pH indicators |
In 1989, Alan Mackay suggested that if chemical synthesis could be used to make L-protein and D-protein enantiomers, it would enable the use of racemic mixtures to crystallize proteins in centrosymmetric space groups. He stated that, because in the X-ray diffraction data obtained from a centrosymmetric crystal the off-... | 1 | Crystallography |
* EAS Award for Outstanding Achievements in the Fields of Analytical Chemistry (2023)
* Martin Medal (2019)
* Ralph N. Adams Award in Bioanalyical Chemistry (2016)
* ACS Award in Chromatography (2017)
* CASSS Award for Outstanding Achievements in Separation Science (2017)
* Marcel Golay Award for Lifetime Achievement ... | 0 | Chromatography + Titration + pH indicators |
In crystallography and solid state physics, the Laue equations relate incoming waves to outgoing waves in the process of elastic scattering, where the photon energy or light temporal frequency does not change upon scattering by a crystal lattice. They are named after physicist Max von Laue (1879–1960).
The Laue equatio... | 1 | Crystallography |
Since its inception as a tool of analytical chemistry, LC-MS/MS spread rapidly and indeed continues to do so in (amongst others) bioanalytical fields. One of the advantages of the technique is its selectivity for many analytes of interest. However, this high selectivity could lead to a misconception that it is always p... | 0 | Chromatography + Titration + pH indicators |
In two dimensions, any lattice can be specified by the length of its two primitive translation vectors and the angle between them. There are an infinite number of possible lattices one can describe in this way. Some way to categorize different types of lattices is desired. One way to do so is to recognize that some lat... | 1 | Crystallography |
The anthocyanins, anthocyanidins with sugar group(s), are mostly 3-glucosides of the anthocyanidins. The anthocyanins are subdivided into the sugar-free anthocyanidin aglycones and the anthocyanin glycosides. As of 2003, more than 400 anthocyanins had been reported, while later literature in early 2006, puts the number... | 0 | Chromatography + Titration + pH indicators |
Goldschmidts tolerance factor (from the German word Toleranzfaktor') is an indicator for the stability and distortion of crystal structures. It was originally only used to describe the perovskite ABO structure, but now tolerance factors are also used for ilmenite.
Alternatively the tolerance factor can be used to calcu... | 1 | Crystallography |
Thermometric titrimetry is particularly suited to the determination of a range of analytes where a precipitate is formed by reaction with the titrant. In some cases, an alternative to traditional potentiometric titration practice can be offered. In other cases, reaction chemistries may be employed for which there is no... | 0 | Chromatography + Titration + pH indicators |
Liquid chromatography is a method of physical separation in which the components of a liquid mixture are distributed between two immiscible phases, i.e., stationary and mobile. The practice of LC can be divided into five categories, i.e., adsorption chromatography, partition chromatography, ion-exchange chromatography,... | 0 | Chromatography + Titration + pH indicators |
Zone axis, a term sometimes used to refer to "high-symmetry" orientations in a crystal, most generally refers to any direction referenced to the direct lattice (as distinct from the reciprocal lattice) of a crystal in three dimensions. It is therefore indexed with direct lattice indices, instead of with Miller indices.... | 1 | Crystallography |
The Green-Kubo relations can be used to calculate the thermal transport properties of a mineral. Since the velocities of the ions are stored at each numerical step, one can calculate the time correlation of later velocities with earlier velocities. The integral of these correlations is related to the Fourier thermal ... | 1 | Crystallography |
Quinaldine red is an indicator that turns from colorless to red between a pH of 1.0–2.2. The image below shows what color quinaldine red would appear as in a given pH.
It is a cationic molecule that undergoes oxidation at different levels of pH. The rate of oxidation of Quinaldine red is in the first order with respect... | 0 | Chromatography + Titration + pH indicators |
Very small amount of carbon is sufficient to stabilize "ScBC". This compound has a broad composition range, namely ScBC with x ≤ 2.2 and y ≤ 0.44. ScBC has a hexagonal crystal structure with space group P6mmm (No. 199) and lattice constants a, b = 1.45501(15) nm and c = 0.84543(16) nm.
There are 19 atomic sites in the ... | 1 | Crystallography |
In polymer systems, the general definition () holds; the elementary constituents are now the monomers making up the chains. However, the structure factor being a measure of the correlation between particle positions, one can reasonably expect that this correlation will be different for monomers belonging to the same ch... | 1 | Crystallography |
In crystallography, the Sayre equation, named after David Sayre who introduced it in 1952, is a mathematical relationship that allows one to calculate probable values for the phases of some diffracted beams. It is used when employing direct methods to solve a structure. Its formulation is the following:
which states ho... | 1 | Crystallography |
It is a possible carcinogen. As "butter yellow", the agent had been used as a food additive in butter and margarine before its toxicity was recognized. | 0 | Chromatography + Titration + pH indicators |
Protein crystallization is the process of formation of a regular array of individual protein molecules stabilized by crystal contacts. If the crystal is sufficiently ordered, it will diffract. Some proteins naturally form crystalline arrays, like aquaporin in the lens of the eye.
In the process of protein crystallizat... | 1 | Crystallography |
IUPAC defines the temperature programmed chromatography Kovats index equation:
* & retention times of trailing and heading n-alkanes, respectively.
NOTE: TPGC index does depend on temperature program, gas velocity and the column used !
ASTM method D6730 defines the temperature programmed chromatography Kovats index eq... | 0 | Chromatography + Titration + pH indicators |
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