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To distinguish whether the geometry of the coordination center is trigonal bipyramidal or square pyramidal, the (originally just ) parameter was proposed by Addison et al.:
where: are the two greatest valence angles of the coordination center.
When is close to 0 the geometry is similar to square pyramidal, while if ... | 1 | Crystallography |
The chromatographic purification of proteins from complex mixtures can be quite challenging, particularly when the mixtures contain similarly retained proteins or when it is desired to enrich trace components in the feed. Further, column loading is often limited when high resolutions are required using traditional mode... | 0 | Chromatography + Titration + pH indicators |
There are several ways to mathematically define quasicrystalline patterns. One definition, the "cut and project" construction, is based on the work of Harald Bohr (mathematician brother of Niels Bohr). The concept of an almost periodic function (also called a quasiperiodic function) was studied by Bohr, including work ... | 1 | Crystallography |
Amorphous silicon (a-Si) is a popular solar cell material owing to its low cost and ease of production. Owing to disordered structure (Urbach tail), its absorption extends to the energies below the band gap resulting in a wide-range spectral response; however, it has a relatively low solar cell efficiency. Protocrystal... | 1 | Crystallography |
For the hexagonal close-packed structure the derivation is similar. Here the unit cell (equivalent to 3 primitive unit cells) is a hexagonal prism containing six atoms (if the particles in the crystal are atoms). Indeed, three are the atoms in the middle layer (inside the prism); in addition, for the top and bottom lay... | 1 | Crystallography |
Modified (or screened) methyl orange, an indicator consisting of a solution of methyl orange and xylene cyanol, changes from grey-violet to green as the solution becomes more basic. | 0 | Chromatography + Titration + pH indicators |
Reflection high energy electron diffraction - total reflection angle X-ray spectroscopy is a technique for monitoring the chemical composition of crystals. RHEED-TRAXS analyzes X-ray spectral lines emitted from a crystal as a result of electrons from a RHEED gun colliding with the surface.
RHEED-TRAXS is preferential t... | 1 | Crystallography |
ScBCSi (x = 0.52, y = 1.42, z = 1.17 and w = 0.02) has a hexagonal crystal structure with space group Pm2 (No. 187) and lattice constants a = b = 1.43055(8) and c = 2.37477(13) nm. Single crystals of this compound were obtained as an intergrowth phase in a float-zoned single crystal of ScBCSi. This phase is not describ... | 1 | Crystallography |
The Collaborative Computational Project Number 4 in Protein Crystallography (CCP4) was set up in 1979 in the United Kingdom to support collaboration between researchers working in software development and assemble a comprehensive collection of software for structural biology. The CCP4 core team is located at the Resear... | 1 | Crystallography |
In addition to yttrium, a wide range of rare-earth elements from Nd to Lu, except for Eu, can form REB compounds. Seybolt discovered the compound YB in 1960 and its structure was solved by Richards and Kasper in 1969. They reported that YB has a face-centered cubic structure with space group Fmc (No. 226) and lattice ... | 1 | Crystallography |
The most common type of mass spectrometer (MS) associated with a gas chromatograph (GC) is the quadrupole mass spectrometer, sometimes referred to by the Hewlett-Packard (now Agilent) trade name "Mass Selective Detector" (MSD). Another relatively common detector is the ion trap mass spectrometer. Additionally one may f... | 0 | Chromatography + Titration + pH indicators |
When dissolved in water, the dye has a blue-violet colour with an absorbance maximum at 590 nm and an extinction coefficient of 87,000 M cm. The colour of the dye depends on the acidity of the solution. At a pH of +1.0, the dye is green with absorption maxima at 420 nm and 620 nm, while in a strongly acidic solution (p... | 0 | Chromatography + Titration + pH indicators |
The reciprocal lattice to a BCC lattice is the FCC lattice, with a cube side of .
It can be proven that only the Bravais lattices which have 90 degrees between (cubic, tetragonal, orthorhombic) have primitive translation vectors for the reciprocal lattice, , parallel to their real-space vectors. | 1 | Crystallography |
RHEED users construct Ewalds spheres to find the crystallographic properties of the sample surface. Ewalds spheres show the allowed diffraction conditions for kinematically scattered electrons in a given RHEED setup. The diffraction pattern at the screen relates to the Ewalds sphere geometry, so RHEED users can directl... | 1 | Crystallography |
The APE(X)C, or All Purpose Electronic (X) Computer series was designed by Andrew Donald Booth at Birkbeck College, London in the early 1950s. His work on the APE(X)C series was sponsored by the British Rayon Research Association. Although the naming conventions are slightly unclear, it seems the first model belonged... | 1 | Crystallography |
Phenolphthalein can be synthesized by condensation of phthalic anhydride with two equivalents of phenol under acidic conditions. It was discovered in 1871 by Adolf von Baeyer.
The reaction can also be catalyzed by a mixture of zinc chloride and thionyl chloride. | 0 | Chromatography + Titration + pH indicators |
Integrating traditional and modern methods is a useful way to process albumin.
There are three main steps that combine Cohn fractionation with chromatography: 1) factors I, II, and III are removed via cold ethanol fractionation, 2) Sepharose fast flow ion exchange and sepharose fast flow chromatography procedures are r... | 0 | Chromatography + Titration + pH indicators |
Content of anthocyanins in the leaves of colorful plant foods such as purple corn, blueberries, or lingonberries, is about ten times higher than in the edible kernels or fruit.
The color spectrum of grape berry leaves may be analysed to evaluate the amount of anthocyanins. Fruit maturity, quality, and harvest time may ... | 0 | Chromatography + Titration + pH indicators |
A tube filled with a glucose phosphate broth is inoculated with a sterile transfer loop. The tube is incubated at for 2–5 days. After incubation, 2.5 ml of the medium are transferred to another tube. Five drops of the pH indicator methyl red is added to this tube. The tube is gently rolled between the palms to dispers... | 0 | Chromatography + Titration + pH indicators |
The preferential alignment is a criterion of an orientation of a molecule or atom. The preferential alignment can be related to the formation of the crystal structure of an amorphous structure.
For a polymer material with liquid crystals, the liquid crystals are molecules shaped like rigid rods. Just as logs being floa... | 1 | Crystallography |
Denaturing High Performance Liquid Chromatography (DHPLC) is a method of chromatography for the detection of base substitutions, small deletions or insertions in the DNA. Thanks to its speed and high resolution, this method is particularly useful for finding polymorphisms in DNA.
In practice, the analysis begins with a... | 0 | Chromatography + Titration + pH indicators |
* Books (chronological order):
** Tanner, Brian: X-ray diffraction topography. Pergamon Press (1976)..
** Authier, André and Lagomarsino, Stefano and Tanner, Brian K. (editors): X-Ray and Neutron Dynamical Diffraction – Theory and Applications. Plenum Press / Kluwer Academic Publishers (1996). .
** Bowen, Keith and Ta... | 1 | Crystallography |
ScBC (x = 0.27, y = 1.1, z = 0.2) has an orthorhombic crystal structure with space group Pbam (No. 55) and lattice constants of a = 1.73040(6), b = 1.60738(6) and c = 1.44829(6) nm. This phase is indicated as ScBC (phase IV) in the phase diagram of figure 17. This rare orthorhombic structure has 78 atomic positions in ... | 1 | Crystallography |
1. Comprehensive Conversion: The reactor converts all organic compounds to methane, whereas traditional methanizers typically only convert CO and CO2. This comprehensive conversion results in a more uniform response and more sensitive detection for a wider range of organic species.
2. Resilience to Poisoning: The react... | 0 | Chromatography + Titration + pH indicators |
CrysTBox (Crystallographic Tool Box) is a suite of computer tools designed to accelerate material research based on transmission electron microscope images via highly accurate automated analysis and interactive visualization. Relying on artificial intelligence and computer vision, CrysTBox makes routine crystallographi... | 1 | Crystallography |
In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessarily have unit size, or even a particular size at all. Rather, the primitive c... | 1 | Crystallography |
The ratio of activities of a solute, A in an aqueous/organic system will remain constant and independent of the total quantity of A (hence ), so at any given temperature:
Distribution constants are useful as they allow the calculation of the concentration of remaining analyte in the solution, even after a number of sol... | 0 | Chromatography + Titration + pH indicators |
Crystallographic directions are lines linking nodes (atoms, ions or molecules) of a crystal. Similarly, crystallographic planes are planes linking nodes. Some directions and planes have a higher density of nodes; these dense planes have an influence on the behavior of the crystal:
*optical properties: in condensed matt... | 1 | Crystallography |
Phenolphthalein ( ) is a chemical compound with the formula CHO and is often written as "HIn", "HPh", "phph" or simply "Ph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions. It belongs t... | 0 | Chromatography + Titration + pH indicators |
* Orbifold signature:
* Coxeter notation (rectangular): [((∞,2),(∞,2))]
* Coxeter notation (square): [4,4]
* Lattice: rectangular
* Point group: D
* The group pgg contains two rotation centres of order two (180°), and glide reflections in two perpendicular directions. The centres of rotation are not locate... | 1 | Crystallography |
Usually when describing a space geometrically, a coordinate system is used which consists of a choice of origin and a basis of linearly independent, non-coplanar basis vectors , where is the dimension of the space being described. With reference to this coordinate system, each point in the space can be specified by ... | 1 | Crystallography |
Though the many advances of HPLC and monoliths are highly visible within the confines of the analytical and pharmaceutical industries, it is unlikely that general society is aware of these developments. Currently, consumers may witness technology developments in the analytical sciences industry in the form of a broader... | 0 | Chromatography + Titration + pH indicators |
The set of databases includes data from International Tables of Crystallography, Vol. A: Space-Group Symmetry, and the data of maximal subgroups of space groups as listed in International Tables of Crystallography, Vol. A1: Symmetry relations between space groups. A k-vector database with Brillouin zone figures and cla... | 1 | Crystallography |
The eluent or eluant is the "carrier" portion of the mobile phase. It moves the analytes through the chromatograph. In liquid chromatography, the eluent is the liquid solvent; in gas chromatography, it is the carrier gas. | 0 | Chromatography + Titration + pH indicators |
APCI generally suffers less ion suppression than ESI, as discussed previously. Where possible, if ion suppression is unavoidable it may be advisable to switch from ESI to APCI. If this is not possible, it may be useful to switch the ESI ionisation mode from positive to negative. Since fewer compounds are ionisable in n... | 0 | Chromatography + Titration + pH indicators |
The operating principle of CCC equipment requires a column consisting of a tube coiled around a bobbin. The bobbin is rotated in a double-axis gyratory motion (a cardioid), which causes a variable g-force to act on the column during each rotation. This motion causes the column to see one partitioning step per revolutio... | 0 | Chromatography + Titration + pH indicators |
Anionic and cationic surfactants can be determined thermometrically by titrating one type against the other. For instance, benzalkonium chloride (a quaternary-type cationic surfactant) may be determined in cleaners and algaecides for swimming pools and spas by titrating with a standard solution of sodium dodecyl sulfat... | 0 | Chromatography + Titration + pH indicators |
HPTLC finds extensive application in various fields, including pharmaceutical industries, clinical chemistry, forensic chemistry, biochemistry, cosmetology, food and drug analysis, environmental analysis, and more, owing to its numerous advantages. It distinguishes itself by being the only chromatographic method capabl... | 0 | Chromatography + Titration + pH indicators |
An SADP is acquired under parallel electron illumination. In the case of convergent beam, a convergent beam electron diffraction (CBED) is achieved. The beam used in SAD is broad illuminating a wide sample area. In order to analyze only a specific sample area, the selected area aperture in the image plane is used. This... | 1 | Crystallography |
The van Deemter equation relates height equivalent to a theoretical plate (HETP) of a chromatographic column to the various flow and kinetic parameters which cause peak broadening, as follows:
Where
* HETP = a measure of the resolving power of the column [m]
* A = Eddy-diffusion parameter, related to channeling throu... | 0 | Chromatography + Titration + pH indicators |
For calculating concentrations, an ICE table can be used. ICE stands for initial, change, and equilibrium.
The pH of a weak acid solution being titrated with a strong base solution can be found at different points along the way. These points fall into one of four categories:
# initial pH
# pH before the equivalence poi... | 0 | Chromatography + Titration + pH indicators |
Standard column chromatography consists of a solid stationary phase and a liquid mobile phase, while gas chromatography (GC) uses a solid or liquid stationary phase on a solid support and a gaseous mobile phase. By contrast, in liquid-liquid chromatography, both the mobile and stationary phases are liquid. The contrast... | 0 | Chromatography + Titration + pH indicators |
It may cause irritation. Its toxicological properties have not been fully investigated. Harmful if swallowed, Acute Toxicity. Only Hazardous when percent values are above 10%. | 0 | Chromatography + Titration + pH indicators |
Cubic materials are special orthotropic materials that are invariant with respect to 90° rotations with respect to the principal axes, i.e., the material is the same along its principal axes. Due to these additional symmetries the stiffness tensor can be written with just three different material properties like
The in... | 1 | Crystallography |
The Wigner–Seitz cell, named after Eugene Wigner and Frederick Seitz, is a primitive cell which has been constructed by applying Voronoi decomposition to a crystal lattice. It is used in the study of crystalline materials in crystallography.
The unique property of a crystal is that its atoms are arranged in a regular t... | 1 | Crystallography |
Bravais lattices, also referred to as space lattices, describe the geometric arrangement of the lattice points, and therefore the translational symmetry of the crystal. The three dimensions of space afford 14 distinct Bravais lattices describing the translational symmetry. All crystalline materials recognized today, no... | 1 | Crystallography |
The basic working principle of diffraction topography is as follows:
An incident, spatially extended beam (mostly of X-rays, or neutrons) impinges on a sample.
The beam may be either monochromatic, i.e. consist one single wavelength of X-rays or neutrons, or polychromatic, i.e. be composed of a mixture of wavelengths ... | 1 | Crystallography |
There have been a few technical issues that have limited adoption of SFC technology in the past. First of all, is the need to keep a high gas pressure in the operating conditions. High-pressure vessels are expensive and bulky, and special materials are often needed to avoid dissolving gaskets and O-rings in the superc... | 0 | Chromatography + Titration + pH indicators |
The injection valve is a motorized valve which links the mixer and sample loop to the column. Typically the valve has three positions for loading the sample loop, for injecting the sample from the loop into the column, and for connecting the pumps directly to the waste line to wash them or change buffer solutions. The ... | 0 | Chromatography + Titration + pH indicators |
Gadolinium is given to patients for magnetic resonance imaging, or an MRI.It is used as a contrast agent for the exam to improve clarity of the images formed. However, it can react in the human body and have detrimental effects. Therefore, the agent should be removed. One of these gadolinium based agents is gadodiamide... | 0 | Chromatography + Titration + pH indicators |
There are many types of titrations with different procedures and goals. The most common types of qualitative titration are acid–base titrations and redox titrations. | 0 | Chromatography + Titration + pH indicators |
In solid-state physics and crystallography, a crystal structure is described by a unit cell repeating periodically over space. There are an infinite number of choices for unit cells, with different shapes and sizes, which can describe the same crystal, and different choices can be useful for different purposes.
Say tha... | 1 | Crystallography |
A common problem to X-ray crystallography and electron crystallography is radiation damage, by which especially organic molecules and proteins are damaged as they are being imaged, limiting the resolution that can be obtained. This is especially troublesome in the setting of electron crystallography, where that radiat... | 1 | Crystallography |
TLC helps show the purity of a sample. A pure sample should only contain one spot by TLC. TLC is also useful for small-scale purification. Because the separated compounds will be on different areas of the plate, a scientist can scrape off the stationary phase particles containing the desired compound and dissolve them ... | 0 | Chromatography + Titration + pH indicators |
The APPI interface for LC–MS was developed simultaneously by Bruins and Syage in 2000. APPI is another LC–MS ion source/ interface for the analysis of neutral compounds that cannot be ionized using ESI. This interface is similar to the APCI ion source, but instead of a corona discharge, the ionization occurs by using p... | 0 | Chromatography + Titration + pH indicators |
It can be shown that there are four types of Euclidean plane isometries. (Note: the notations for the types of isometries listed below are not completely standardised.) | 1 | Crystallography |
The Pearson symbol should only be used to designate simple structures (elements, some binary compound) where the number of atoms per unit cell equals, ideally, the number of translationally equivalent points. | 1 | Crystallography |
*Significant improvement of resolution in data collection
*Reduced or eliminated radiation damage in crystals | 1 | Crystallography |
Multiple isomorphous replacement (MIR), where heavy atoms are inserted into structure (usually by synthesizing proteins with analogs or by soaking) | 1 | Crystallography |
The development of the APCI interface for LC–MS started with Horning and collaborators in the early 1973. However, its commercial application was introduced at the beginning of the 1990s after Henion and collaborators improved the LC–APCI–MS interface in 1986. The APCI ion source/ interface can be used to analyze small... | 0 | Chromatography + Titration + pH indicators |
Butter yellow was synthesized by Peter Griess in the 1860s at the Royal College of Chemistry in London. The dye was used to dye butter in Germany and other parts of the world during the latter half of the 19th century and the beginning of the 20th before being phased out in the 1930s and 40s. It was in the 1930s that r... | 0 | Chromatography + Titration + pH indicators |
SFC has been used primarily for separation of chiral molecules, mainly those which required normal phase conditions. While the mobile phase is a fluid in the supercritical state, the stationary phase is packed inside columns similar to those used in liquid chromatography. Since the use of normal phase mode of chromatog... | 0 | Chromatography + Titration + pH indicators |
Of the 32 crystallographic point groups, 10 are polar:
The space groups associated with a polar point group do not have a discrete set of possible origin points that are unambiguously determined by symmetry elements.
When materials having a polar point group crystal structure are heated or cooled, they may temporarily ... | 1 | Crystallography |
There are two types of pumps available for uniform delivery of relatively small liquid volumes for GPC: piston or peristaltic pumps. The delivery of a constant flow free of fluctuations is especially important to the precision of the GPC analysis, as the flow-rate is used for the calibration of the molecular weight, or... | 0 | Chromatography + Titration + pH indicators |
In addition to the operations of the point group, the space group of the crystal structure contains translational symmetry operations. These include:
*Pure translations, which move a point along a vector
*Screw axes, which rotate a point around an axis while translating parallel to the axis.
*Glide planes, which reflec... | 1 | Crystallography |
After crystallization, often some solidified flux remains on the surface or inside the desired crystal. This flux may cause defects in the crystal due to the different thermal expansivities of the flux and crystal. A solvent (typically an acid or a base) can dissolve the flux, but its difficult to find a solvent that d... | 1 | Crystallography |
Cleavage forms parallel to crystallographic planes:
*Basal, pinacoidal, or planar cleavage occurs when there is only cleavage plane. Talc has basal cleavage. Mica (like muscovite or biotite) also has basal cleavage; this is why mica can be peeled into thin sheets.
*Prismatic cleavage occurs when there are cleavage pl... | 1 | Crystallography |
Capillary electrophoresis (CE) is a family of electrokinetic separation methods performed in submillimeter diameter capillaries and in micro- and nanofluidic channels. Very often, CE refers to capillary zone electrophoresis (CZE), but other electrophoretic techniques including capillary gel electrophoresis (CGE), capil... | 0 | Chromatography + Titration + pH indicators |
The Knudsen effusion cell was developed by Martin Knudsen (1871–1949). A typical Knudsen cell contains a crucible (made of pyrolytic boron nitride, quartz, tungsten or graphite), heating filaments (often made of metal tantalum), water cooling system, heat shields, and an orifice shutter. | 1 | Crystallography |
Malachite green is an organic compound that is used as a dyestuff and controversially as an antimicrobial in aquaculture. Malachite green is traditionally used as a dye for materials such as silk, leather, and paper. Despite its name the dye is not prepared from the mineral malachite; the name just comes from the simil... | 0 | Chromatography + Titration + pH indicators |
In the Euclidean plane, we have the following possibilities.
*; [ ] Identity
:Two reflections in the same mirror restore each point to its original position. All points are left fixed. Any pair of identical mirrors has the same effect.
*; [] Reflection
:As Alice found through the looking-glass, a single mirror causes ... | 1 | Crystallography |
Perovskites can be deposited as epitaxial thin films on top of other perovskites, using techniques such as pulsed laser deposition and molecular-beam epitaxy. These films can be a couple of nanometres thick or as small as a single unit cell. The well-defined and unique structures at the interfaces between the film and ... | 1 | Crystallography |
The APE(X)C series included the following machines:
* APE(X)C: Birkbeck College, London, first time operated in May 1952, ready for use at the end of 1953
* APE(N)C: Board of Mathematical Machines, Oslo (N likely stands for Norway), also known as NUSSE
* APE(H)C: British Tabulating Machine Company (It is unclear what H... | 1 | Crystallography |
Quantum crystallography is a branch of crystallography that investigates crystalline materials within the framework of quantum mechanics, with analysis and representation, in position or in momentum space, of quantities like wave function, electron charge and spin density, density matrices and all properties related to... | 1 | Crystallography |
Convergent beam electron diffraction (CBED) is an electron diffraction technique where a convergent or divergent beam (conical electron beam) of electrons is used to study materials. | 1 | Crystallography |
The relationship between fractional and Cartesian coordinates can be described by the matrix transformation :
Similarly, the Cartesian coordinates can be converted back to fractional coordinates using the transformation : | 1 | Crystallography |
Mixed-mode chromatography (MMC), or multimodal chromatography, refers to chromatographic methods that utilize more than one form of interaction between the stationary phase and analytes in order to achieve their separation. What is distinct from conventional single-mode chromatography is that the secondary interactions... | 0 | Chromatography + Titration + pH indicators |
"Euhedral" is derived from the Greek eu meaning "well, good" and hedron meaning a seat or a face of a solid. | 1 | Crystallography |
For an infinite three-dimensional lattice , defined by its primitive vectors and the subscript of integers , its reciprocal lattice with the integer subscript can be determined by generating its three reciprocal primitive vectors
where is the scalar triple product. The choice of these is to satisfy as the known ... | 1 | Crystallography |
The intense coloring of the molecule is generated by the absorption of specific wavelengths of light by the pi bonds. These bonds are ordinarily excited by light in the orange region of the spectrum, causing the molecule to appear blue. When the molecule interacts with protons from an acid the bonds become harder to ex... | 0 | Chromatography + Titration + pH indicators |
The use of electronic detectors such as X-ray CCD cameras, replacing traditional X-ray film, facilitates topography in many ways. CCDs achieve online readout in (almost) real-time, dispensing experimentalists of the need to develop films in a dark room. Drawbacks with respect to films are the limited dynamic range and,... | 1 | Crystallography |
For a one-dimensional crystal of size
where the factor in parentheses comes from the fact the sum is over nearest-neighbour pairs (), next nearest-neighbours (), ... and for a crystal of planes, there are pairs of nearest neighbours, pairs of next-nearest neighbours, etc. | 1 | Crystallography |
After the molecules travel the length of the column, pass through the transfer line and enter into the mass spectrometer they are ionized by various methods with typically only one method being used at any given time. Once the sample is fragmented it will then be detected, usually by an electron multiplier, which essen... | 0 | Chromatography + Titration + pH indicators |
Centrifugal partition chromatography has been extensively used for isolation and purification of natural products for 40 years. Due to the ability to get very high selectivity, and the ability to tolerate samples containing particulated matter, it is possible to work with direct extracts of biomass, opposed to traditio... | 0 | Chromatography + Titration + pH indicators |
Two-dimensional liquid chromatography (2D-LC) combines two separate analyses of liquid chromatography into one data analysis. Modern 2D liquid chromatography has its origins in the late 1970s to early 1980s. During this time, the hypothesized principles of 2D-LC were being proven via experiments conducted along with su... | 0 | Chromatography + Titration + pH indicators |
SAD analysis is widely used in material research for its relative simplicity and high information value. Once the sample is prepared and examined in a modern transmission electron microscope, the device allows for a routine diffraction acquisition in a matter of seconds. If the images are interpreted correctly, they ca... | 1 | Crystallography |
Liquid chromatography as we know it today really got its start in 1969, when the first modern HPLC was designed and marketed as a nucleic acid analyzer. Columns throughout the 1970s were unreliable, pump flow rates were inconsistent, and many biologically active compounds escaped detection by UV and fluorescence detec... | 0 | Chromatography + Titration + pH indicators |
The origin of the stereographic projection is not known, but it is believed to have been discovered by Ancient Greek astronomers and used for projecting the celestial sphere to the plane so that the motions of stars and planets could be analyzed using plane geometry. Its earliest extant description is found in Ptolemys... | 1 | Crystallography |
* In acids: violet
* At equivalence point (pH 5.2): grey
* In bases: green
Methylene blue functions to change the red-yellow shift of methyl red to a more distinct violet-green shift. | 0 | Chromatography + Titration + pH indicators |
Of the hundreds of facet arrangements that have been used, the most famous is probably the round brilliant cut, used for diamond and many colored gemstones. This first early version of what would become the modern Brilliant Cut is said to have been devised by an Italian named Peruzzi, sometime in the late 17th century.... | 1 | Crystallography |
A wallpaper remains on the whole unchanged under certain isometries, starting with certain translations that confer on the wallpaper a repetitive nature. One of the reasons to be unchanged under certain translations is that it covers the whole plane. No mathematical object in our minds is stuck onto a motionless wall! ... | 1 | Crystallography |
Micelles are composed of surfactant, or detergent, monomers with a hydrophobic moiety, or tail, on one end, and a hydrophilic moiety, or head group, on the other. The polar head group may be anionic, cationic, zwitterionic, or non-ionic. When the concentration of a surfactant in solution reaches its critical micelle ... | 0 | Chromatography + Titration + pH indicators |
After 125 years of study, 1,3,5-trinitrobenzene yielded a second polymorph. The usual form has the space group Pbca, but in 2004, a second polymorph was obtained in the space group Pca2 when the compound was crystallised in the presence of an additive, trisindane. This experiment shows that additives can induce the app... | 1 | Crystallography |
In crystallography and the theory of infinite vertex-transitive graphs, the coordination sequence of a vertex is an integer sequence that counts how many vertices are at each possible distance from . That is, it is a sequence
where each is the number of vertices that are steps away from . If the graph is vertex-tran... | 1 | Crystallography |
Bromocresol purple (BCP) or 5′,5″-dibromo-o-cresolsulfophthalein, is a dye of the triphenylmethane family (triarylmethane dyes) and a pH indicator. It is colored yellow below pH 5.2, and violet above pH 6.8. In its cyclic sulfonate ester form, it has a pK value of 6.3, and is usually prepared as a 0.04% aqueous solutio... | 0 | Chromatography + Titration + pH indicators |
In liquid chromatography:
* Charged aerosol detector electrically charged aerosol is used for the detection of non-UV-absorbing chargeable molecules, especially saccharides and lipids
* Evaporative light scattering detector evaporating non volatile solutes inside a volatile mobile phase for universal detection. used f... | 0 | Chromatography + Titration + pH indicators |
"European Parliament and Council Directive 94/36/EC of 30 June 1994 on colours for use in foodstuffs" harmonized rules and approved Sunset Yellow FCF for use in foodstuffs in the whole of the European Union. Before that time, approved amounts was up to each country, but naming and composition was standardized.
Sunset y... | 0 | Chromatography + Titration + pH indicators |
o-Cresolphthalein is a phthalein dye used as a pH indicator in titrations. It is insoluble in water but soluble in ethanol. Its solution is colourless below pH 8.2, and purple above 9.8. Its molecular formula is CHO. It is used medically to determine calcium levels in the human body, or to synthesize polyamides or poly... | 0 | Chromatography + Titration + pH indicators |
If half of the tetrahedral sites of the parent FCC lattice are filled by ions of opposite charge, the structure formed is the zincblende crystal structure. If all the tetrahedral sites of the parent FCC lattice are filled by ions of opposite charge, the structure formed is the fluorite structure or antifluorite structu... | 1 | Crystallography |
Advantages of HPTLC:
* Provides straightforward information about effects arising from individual compounds in complex or natural samples separated in parallel.
* Combines chromatographic separation with effect-directed detection using enzymatic or biological assays.
* Helps to select important compounds from a sample ... | 0 | Chromatography + Titration + pH indicators |
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