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Crystalloluminescence
Crystalloluminescence is the effect of luminescence produced during crystallization. The phenomenon was first reported in the 1800s from the rapid crystallization of potassium sulfate from an aqueous solution.''Light emission during growth and destruction of crystals. Crystalloluminescence and triboluminescence'', Jeffrey I. Zink, and B. P. Chandra; J. Phys. Chem., 1982, 86 (1), pp 5–7 See also * Physical crystallography before X-rays Physical crystallography before X-rays describes how physical crystallography developed as a science up to the discovery of X-rays by Wilhelm Conrad Röntgen in 1895. In the period before X-rays, crystallography can be divided into three broad are ... References Luminescence Light sources {{physical-chemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Crystallography Before X-rays
Physical crystallography before X-rays describes how physical crystallography developed as a science up to the discovery of X-rays by Wilhelm Conrad Röntgen in 1895. In the period before X-rays, crystallography can be divided into three broad areas: geometric crystallography culminating in the discovery of the 230 space groups in 1891–4, chemical crystallography and physical crystallography. Physical crystallography is concerned with the Mineralogy#Physical properties, physical properties of crystals, such as their Crystal optics, optical, electrical, and magnetic properties. The effect of electromagnetic radiation on crystals is covered in the following sections: #Double refraction, double refraction, #Rotary polarization, rotary polarization, #Conical refraction, conical refraction, #Absorption and pleochroism, absorption and pleochroism, #Luminescence, fluorescence and phosphorescence, luminescence, fluorescence and phosphorescence, #Reflection from opaque materials, reflecti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luminescence
Luminescence is a spontaneous emission of radiation from an electronically or vibrationally excited species not in thermal equilibrium with its environment. A luminescent object emits ''cold light'' in contrast to incandescence, where an object only emits light after heating. Generally, the emission of light is due to the movement of electrons between different energy levels within an atom after excitation by external factors. However, the exact mechanism of light emission in vibrationally excited species is unknown. The dials, hands, scales, and signs of aviation and navigational instruments and markings are often coated with luminescent materials in a process known as ''luminising''. Types * Ionoluminescence, a result of bombardment by fast ions * Radioluminescence, a result of bombardment by ionizing radiation * Electroluminescence, a result of an electric current passed through a substance ** Cathodoluminescence, a result of a luminescent material being struck by elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallization
Crystallization is a process that leads to solids with highly organized Atom, atoms or Molecule, molecules, i.e. a crystal. The ordered nature of a crystalline solid can be contrasted with amorphous solids in which atoms or molecules lack regular organization. Crystallization can occur by various routes including Precipitation (chemistry), precipitation from solution, freezing of a liquid, or Deposition (phase transition), deposition from a gas. Attributes of the resulting crystal can depend largely on factors such as temperature, air pressure, cooling rate, or Solution (chemistry), solute concentration. Crystallization occurs in two major steps. The first is nucleation, the appearance of a crystalline phase from either a Supercooling, supercooled liquid or a supersaturation, supersaturated solvent. The second step is known as crystal growth, which is the increase in the size of particles and leads to a crystal state. An important feature of this step is that loose particles fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Sulfate
Potassium sulfate (US) or potassium sulphate (UK), also called sulphate of potash (SOP), arcanite, or archaically potash of sulfur, is the inorganic compound with formula K2SO4, a white water-soluble solid. It is commonly used in fertilizers, providing both potassium and sulfur. History Potassium sulfate (K2SO4) has been known since early in the 14th century. It was studied by Glauber, Boyle, and Tachenius. In the 17th century, it was named ''arcanuni'' or ''sal duplicatum'', as it was a combination of an acid salt with an alkaline salt. It was also known as ''vitriolic tartar'' and ''Glaser's salt'' or ''sal polychrestum Glaseri'' after the pharmaceutical chemist Christopher Glaser who prepared it and used medicinally. Known as ''arcanum duplicatum'' ("double secret") or ''panacea duplicata'' in pre-modern medicine, it was prepared from the residue ('' caput mortuum'') left over from the production of aqua fortis (nitric acid, HNO3) from nitre (potassium nitrate, KNO3) an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aqueous Solution
An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, also known as sodium chloride (NaCl), in water would be represented as . The word ''aqueous'' (which comes from ''aqua'') means pertaining to, related to, similar to, or dissolved in, water. As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Since water is frequently used as the solvent in experiments, the word solution refers to an aqueous solution, unless the solvent is specified. A ''non-aqueous solution'' is a solution in which the solvent is a liquid, but is not water. Characteristics Substances that are ''hydrophobic'' ('water-fearing') do not dissolve well in water, whereas those that are '' hydrophilic'' ('water-friendly') do. An example of a hydrophilic substance is sodium chloride. In an aqueous solution the hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
