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50-536: CSCL can refer to: Caesium chloride (CsCl), a chemical compound. Computer Supported Collaborative Learning , a research topic on supporting collaborative learning with the assistance of computer artifacts. China Shipping Container Lines , a containerized marine shipping company, based in Shanghai China. Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with

100-444: A bi-layered parallel fiber hygroscopic cell physiology to control the awn's movement for dispersal and self-burial of seeds. Alignment of cellulose fibrils in the awn's controlling cell wall determines direction of movement. If fiber alignments are tilted, non-parallel venation, a helix develops and awn movement becomes twisting (coiling) instead of bending; e.g. coiling occurs in awns of Erodium , and Hesperostipa . Hygroscopicity

150-503: A crunchy, crisp cookie (British English: biscuit) versus a soft, chewy cake. Sugars such as honey , brown sugar , and molasses are examples of sweeteners used to create moister and chewier cakes. Several hygroscopic approaches to harvest atmospheric moisture have been demonstrated and require further development to assess their potentials as a viable water source. Hygroscopic glues are candidates for commercial development. The most common cause of synthetic glue failure at high humidity

200-481: A major contribution from CsCl, were being produced annually around the 1970s and 2000s worldwide. Caesium chloride enriched with caesium-137 for radiation therapy applications is produced at a single facility Mayak in the Ural Region of Russia and is sold internationally through a UK dealer. The salt is synthesized at 200 °C because of its hygroscopic nature and sealed in a thimble-shaped steel container which

250-453: A primitive cubic lattice with a two-atom basis, where both atoms have eightfold coordination. The chloride atoms lie upon the lattice points at the corners of the cube, while the caesium atoms lie in the holes in the center of the cubes; an alternative and exactly equivalent 'setting' has the caesium ions at the corners and the chloride ion in the center. This structure is shared with CsBr and CsI and many binary metallic alloys . In contrast,

300-569: A relatively high solubility in formic acid (1077 g/L at 18 °C) and hydrazine ; medium solubility in methanol (31.7 g/L at 25 °C) and low solubility in ethanol (7.6 g/L at 25 °C), sulfur dioxide (2.95 g/L at 25 °C), ammonia (3.8 g/L at 0 °C), acetone (0.004% at 18 °C), acetonitrile (0.083 g/L at 18 °C), ethylacetate and other complex ethers , butanone , acetophenone , pyridine and chlorobenzene . Despite its wide band gap of about 8.35 eV at 80 K, caesium chloride weakly conducts electricity, and

350-442: A solution with high density and yet relatively low viscosity, and CsCl suits it because of its high solubility in water, high density owing to the large mass of Cs, as well as low viscosity and high stability of CsCl solutions. Caesium chloride is rarely used in organic chemistry. It can act as a phase transfer catalyst reagent in selected reactions. One of these reactions is the synthesis of glutamic acid derivatives where TBAB

400-403: A source containing about 93 grams of CsCl, was stolen from an abandoned hospital and forced open by two scavengers. The blue glow emitted in the dark by the radioactive caesium chloride attracted the thieves and their relatives who were unaware of the associated dangers and spread the powder. This resulted in one of the worst radiation spill accidents in which 4 people died within a month from

450-412: A stress that curls the cover toward the laminated side. This is similar to the function of a thermostat's bimetallic strip . Inexpensive dial-type hygrometers make use of this principle using a coiled strip. Deliquescence is the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution. Deliquescence occurs when the vapour pressure of

500-599: A strong affinity for water and tendency to absorb moisture from the atmosphere if exposed to it. Unlike hygroscopy, however, deliquescence involves absorbing sufficient water to form an aqueous solution . Most deliquescent materials are salts , including calcium chloride , magnesium chloride , zinc chloride , ferric chloride , carnallite , potassium carbonate , potassium phosphate , ferric ammonium citrate , ammonium nitrate , potassium hydroxide , and sodium hydroxide . Owing to their very high affinity for water, these substances are often used as desiccants , which

550-428: A variety of double salts with other chlorides. Examples include 2CsCl·BaCl 2 , 2CsCl·CuCl 2 , CsCl·2CuCl and CsCl·LiCl, and with interhalogen compounds: Caesium chloride occurs naturally as an impurity in the halide minerals carnallite (KMgCl 3 ·6H 2 O with up to 0.002% CsCl), sylvite (KCl) and kainite (MgSO 4 ·KCl·3H 2 O), and in mineral waters. For example, the water of Bad Dürkheim spa, which

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600-468: A viewing or imaging mode. It did begin that way, with the word hygroscope referring in the 1790s to measuring devices for humidity level. These hygroscopes used materials, such as certain animal hairs, that appreciably changed shape and size when they became damp. Such materials were then said to be hygroscopic because they were suitable for making a hygroscope. Eventually, the word hygroscope ceased to be used for any such instrument in modern usage , but

650-590: A wide variety of other substances. If a compound dissolves in water, then it is considered to be hydrophilic . Zinc chloride and calcium chloride , as well as potassium hydroxide and sodium hydroxide (and many different salts ), are so hygroscopic that they readily dissolve in the water they absorb: this property is called deliquescence . Not only is sulfuric acid hygroscopic in concentrated form but its solutions are hygroscopic down to concentrations of 10% v/v or below. A hygroscopic material will tend to become damp and cakey when exposed to moist air (such as

700-474: Is 2300 mg per kilogram of body weight for oral administration and 910 mg/kg for intravenous injection. The mild toxicity of CsCl is related to its ability to lower the concentration of potassium in the body and partly substitute it in biochemical processes. When taken in large quantities, however, can cause a significant imbalance in potassium and lead to hypokalemia , arrhythmia , and acute cardiac arrest . However, caesium chloride powder can irritate

750-405: Is a common mechanism of seed dispersal as the movement of dead tissues respond to hygrometric variation, e.g. spore release from the fertile margins of Onoclea sensibilis . Movement occurs when plant tissue matures, dies and desiccates, cell walls drying, shrinking; and also when humidity re-hydrates plant tissue, cell walls enlarging, expanding. The direction of the resulting force depends upon

800-461: Is a general term used to describe a material's ability to absorb moisture from the environment. There is no standard quantitative definition of hygroscopicity, so generally the qualification of hygroscopic and non-hygroscopic is determined on a case-by-case basis. For example, pharmaceuticals that pick up more than 5% by mass, between 40 and 90% relative humidity at 25 °C, are described as hygroscopic, while materials that pick up less than 1%, under

850-470: Is also an application for concentrated sulfuric and phosphoric acids . Some deliquescent compounds are used in the chemical industry to remove water produced by chemical reactions (see drying tube ). Hygroscopy appears in both plant and animal kingdoms, the latter benefiting via hydration and nutrition. Some amphibian species secrete a hygroscopic mucus that harvests moisture from the air. Orb web building spiders produce hygroscopic secretions that preserve

900-486: Is tetrabutylammonium bromide (interphase catalyst) and CPME is a cyclopentyl methyl ether (solvent). Another reaction is substitution of tetranitromethane where DMF is dimethylformamide (solvent). Caesium chloride is a reagent in traditional analytical chemistry used for detecting inorganic ions via the color and morphology of the precipitates. Quantitative concentration measurement of some of these ions, e.g. Mg , with inductively coupled plasma mass spectrometry ,

950-434: Is then enclosed into another steel casing. The sealing is required to protect the salt from moisture. In the laboratory, CsCl can be obtained by treating caesium hydroxide , carbonate , caesium bicarbonate, or caesium sulfide with hydrochloric acid: Caesium chloride is the main precursor to caesium metal by high-temperature reduction: A similar reaction – heating CsCl with calcium in vacuum in presence of phosphorus –

1000-410: Is used in the preparation of electrically conducting glasses and screens of cathode ray tubes. In conjunction with rare gases CsCl is used in excimer lamps and excimer lasers . Other uses include activation of electrodes in welding; manufacture of mineral water, beer and drilling muds ; and high-temperature solders. High-quality CsCl single crystals have a wide transparency range from UV to

1050-406: Is used to evaluate the hardness of water. It is also used for detection of the following ions: The American Cancer Society states that "available scientific evidence does not support claims that non-radioactive cesium chloride supplements have any effect on tumors." The Food and Drug Administration has warned about safety risks, including significant heart toxicity and death, associated with

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1100-431: Is widely used in isopycnic centrifugation for separating various types of DNA . It is a reagent in analytical chemistry , where it is used to identify ions by the color and morphology of the precipitate. When enriched in radioisotopes , such as CsCl or CsCl, caesium chloride is used in nuclear medicine applications such as treatment of cancer and diagnosis of myocardial infarction . Another form of cancer treatment

1150-522: The mucous membranes and cause asthma . Because of its high solubility in water, caesium chloride is highly mobile and can even diffuse through concrete. This is a drawback for its radioactive form which urges a search for less chemically mobile radioisotope materials. Commercial sources of radioactive caesium chloride are well sealed in a double steel enclosure. However, in the Goiânia accident in Brazil , such

1200-419: The architecture of the tissue and is capable of producing bending, twisting or coiling movements. Typical of hygroscopic movement are plant tissues with "closely packed long (columnar) parallel thick-walled cells (that) respond by expanding longitudinally when exposed to humidity and shrinking when dried (Reyssat et al., 2009)". Cell orientation, pattern structure (annular, planar, bi-layered or tri-layered) and

1250-419: The coefficient of hygroscopic contraction (CHC)—the difference between the two terms being a difference in sign convention. Differences in hygroscopy can be observed in plastic-laminated paperback book covers—often, in a suddenly moist environment, the book cover will curl away from the rest of the book. The unlaminated side of the cover absorbs more moisture than the laminated side and increases in area, causing

1300-491: The conductivity is not electronic but ionic . The conductivity has a value of the order 10 S/cm at 300 °C. It occurs through nearest-neighbor jumps of lattice vacancies, and the mobility is much higher for the Cl than Cs vacancies. The conductivity increases with temperature up to about 450 °C, with an activation energy changing from 0.6 to 1.3 eV at about 260 °C. It then sharply drops by two orders of magnitude because of

1350-405: The double salt with hydrogen sulfide gives CsCl: High-purity CsCl is also produced from recrystallized Cs [ ICl 2 ] {\displaystyle {\ce {Cs[ICl2]}}} (and Cs [ ICl 4 ] {\displaystyle {\ce {Cs[ICl4]}}} ) by thermal decomposition: Only about 20 tonnes of caesium compounds, with

1400-557: The effects of the opposite-surface's cell orientation control the hygroscopic reaction. Moisture responsive seed encapsulations rely on valves opening when exposed to wetting or drying; discontinuous tissue structures provide such predetermined breaking points (sutures), often implemented via reduced cell wall thickness or seams within bi- or tri-layered structures. Graded distributions varying in density and/or cell orientation focus hygroscopic movement, frequently observed as biological actuators (a hinge function); e.g. pinecones ( Pinus spp. ),

1450-407: The event of an accident. For instance, radiothermal generators (RTGs) often use strontium titanate , which is insoluble in water. For teletherapy sources, however, the radioactive density ( Ci in a given volume) needs to be very high, which is not possible with known insoluble caesium compounds. A thimble-shaped container of radioactive caesium chloride provides the active source. Caesium chloride

1500-517: The exposure, 20 showed signs of radiation sickness , 249 people were contaminated with radioactive caesium chloride, and about a thousand received a dose exceeding a yearly amount of background radiation. More than 110,000 people overwhelmed the local hospitals, and several city blocks had to be demolished in the cleanup operations. In the first days of the contamination, stomach disorders and nausea due to radiation sickness were experienced by several people, but only after several days one person associated

1550-495: The express purpose of maintaining moisture content , hygroscopic materials are known as humectants . Materials and compounds exhibit different hygroscopic properties, and this difference can lead to detrimental effects, such as stress concentration in composite materials . The volume of a particular material or compound is affected by ambient moisture and may be considered its coefficient of hygroscopic expansion (CHE) (also referred to as CME, or coefficient of moisture expansion) or

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1600-432: The ice plant ( Aizoaceae spp. ) and the wheat awn ( Triticum spp. ), described below. Two angiospermae families have similar methods of dispersal, though method of implementation varies within family: Geraniaceae family examples are the common stork's-bill ( Erodium cicutarium ) and geraniums ( Pelargonium sp. ); Poaceae family, Needle-and-Thread ( Hesperostipa comata ) and wheat ( Triticum spp. ). All rely upon

1650-471: The infrared and therefore had been used for cuvettes, prisms and windows in optical spectrometers; this use was discontinued with the development of less hygroscopic materials. CsCl is a potent inhibitor of HCN channels, which carry the h-current in excitable cells such as neurons. Therefore, it can be useful in electrophysiology experiments in neuroscience. Caesium chloride has a low toxicity to humans and animals. Its median lethal dose (LD 50 ) in mice

1700-460: The other alkaline halides have the sodium chloride (rocksalt) structure. When both ions are similar in size (Cs ionic radius 174 pm for this coordination number, Cl 181 pm) the CsCl structure is adopted, when they are different (Na ionic radius 102 pm, Cl 181 pm) the sodium chloride structure is adopted. Upon heating to above 445 °C, the normal caesium chloride structure (α-CsCl) converts to

1750-546: The phase transition from the α-CsCl to β-CsCl phase. The conductivity is also suppressed by application of pressure (about 10 times decrease at 0.4 GPa) which reduces the mobility of lattice vacancies. Caesium chloride completely dissociates upon dissolution in water, and the Cs cations are solvated in dilute solution. CsCl converts to caesium sulfate upon being heated in concentrated sulfuric acid or heated with caesium hydrogen sulfate at 550–700 °C: Caesium chloride forms

1800-405: The physical side, a physico-chemical process. Berthelot's principle of reversibility, briefly- that water dried from plant tissue could be restored hygroscopically, was published in "Recherches sur la desiccation des plantes et des tissues végétaux; conditions d'équilibre et de réversibilité," ( Annales de Chimie et de Physique , April 1903). Léo Errera viewed hygroscopicity from perspectives of

1850-553: The physicist and the chemist. His memoir "Sur l'Hygroscopicité comme cause de l'action physiologique à distance" ( Recueil de l'lnstitut Botanique Léo Errera, Université de Bruxelles , tome vi., 1906) provided a hygroscopy definition that remains valid to this day. Hygroscopy is "exhibited in the most comprehensive sense, as displayed Hygroscopic substances include cellulose fibers (such as cotton and paper), sugar , caramel , honey , glycerol , ethanol , wood , methanol , sulfuric acid , many fertilizer chemicals, many salts and

1900-569: The salt inside salt shakers during humid weather). Because of their affinity for atmospheric moisture , desirable hygroscopic materials might require storage in sealed containers. Some hygroscopic materials, e.g., sea salt and sulfates, occur naturally in the atmosphere and serve as cloud seeds , cloud condensation nuclei (CCNs). Being hygroscopic, their microscopic particles provide an attractive surface for moisture vapour to condense and form droplets. Modern-day human cloud seeding efforts began in 1946. When added to foods or other materials for

1950-1151: The same conditions are regarded as non-hygroscopic. The amount of moisture held by hygroscopic materials is usually proportional to the relative humidity. Tables containing this information can be found in many engineering handbooks and is also available from suppliers of various materials and chemicals. Hygroscopy also plays an important role in the engineering of plastic materials. Some plastics, e. g. nylon , are hygroscopic while others are not. Many engineering polymers are hygroscopic, including nylon , ABS , polycarbonate , cellulose , carboxymethyl cellulose , and poly(methyl methacrylate) (PMMA, plexiglas , perspex ). Other polymers, such as polyethylene and polystyrene , do not normally absorb much moisture, but are able to carry significant moisture on their surface when exposed to liquid water. Type-6 nylon (a polyamide ) can absorb up to 9.5% of its weight in moisture. The use of different substances' hygroscopic properties in baking are often used to achieve differences in moisture content and, hence, crispiness. Different varieties of sugars are used in different quantities to produce

2000-414: The solution that is formed is less than the partial pressure of water vapour in the air. While some similar forces are at work here, it is different from capillary attraction , a process where glass or other solid substances attract water, but are not changed in the process (e.g., water molecules do not become suspended between the glass molecules). Deliquescence, like hygroscopy, is also characterized by

2050-738: The stickiness and adhesion force of their webs. One aquatic reptile species is able to travel beyond aquatic limitations, onto land, due to its hygroscopic integument . Plants benefit from hygroscopy via hydration and reproduction – demonstrated by convergent evolution examples. Hygroscopic movement (hygrometrically activated movement) is integral in fertilization, seed/spore release, dispersal and germination. The phrase "hygroscopic movement" originated in 1904's " Vorlesungen Über Pflanzenphysiologie ", translated in 1907 as "Lectures on Plant Physiology" ( Ludwig Jost and R.J. Harvey Gibson , Oxford, 1907). When movement becomes larger scale, affected plant tissues are colloquially termed hygromorphs. Hygromorphy

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2100-836: The substance. For example, a finely dispersed hygroscopic powder, such as a salt, may become clumpy over time due to collection of moisture from the surrounding environment. Deliquescent materials are sufficiently hygroscopic that they dissolve in the water they absorb, forming an aqueous solution . Hygroscopy is essential for many plant and animal species' attainment of hydration, nutrition, reproduction and/or seed dispersal . Biological evolution created hygroscopic solutions for water harvesting, filament tensile strength, bonding and passive motion – natural solutions being considered in future biomimetics . The word hygroscopy ( / h aɪ ˈ ɡ r ɒ s k ə p i / ) uses combining forms of hygro- (for moisture or humidity) and -scopy . Unlike any other -scopy word, it no longer refers to

2150-524: The symptoms with the powder and brought a sample to the authorities. Hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment , which is usually at normal or room temperature. If water molecules become suspended among the substance's molecules, adsorbing substances can become physically changed, e.g. changing in volume, boiling point , viscosity or some other physical characteristic or property of

2200-459: The title CSCL . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=CSCL&oldid=541707046 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Caesium chloride Caesium chloride

2250-414: The use of cesium chloride in naturopathic medicine. Caesium chloride composed of radioisotopes such as CsCl and CsCl, is used in nuclear medicine , including treatment of cancer ( brachytherapy ) and diagnosis of myocardial infarction . In the production of radioactive sources, it is normal to choose a chemical form of the radioisotope which would not be readily dispersed in the environment in

2300-674: The word hygroscopic (tending to retain moisture) lived on, and thus also hygroscopy (the ability to do so). Nowadays an instrument for measuring humidity is called a hygrometer ( hygro- + -meter ). Early hygroscopy literature began circa 1880. Studies by Victor Jodin ( Annales Agronomiques , October 1897) focused on the biological properties of hygroscopicity. He noted pea seeds, both living and dead (without germinative capacity), responded similarly to atmospheric humidity, their weight increasing or decreasing in relation to hygrometric variation. Marcellin Berthelot viewed hygroscopicity from

2350-712: The β-CsCl form with the rocksalt structure ( space group Fm 3 m ). The rocksalt structure is also observed at ambient conditions in nanometer-thin CsCl films grown on mica , LiF, KBr and NaCl substrates. Caesium chloride is colorless in the form of large crystals and white when powdered. It readily dissolves in water with the maximum solubility increasing from 1865 g/L at 20 °C to 2705 g/L at 100 °C. The crystals are very hygroscopic and gradually disintegrate at ambient conditions. Caesium chloride does not form hydrates . In contrast to sodium chloride and potassium chloride , caesium chloride readily dissolves in concentrated hydrochloric acid. Caesium chloride has also

2400-627: Was first reported in 1905 by the French chemist M. L. Hackspill and is still used industrially. Caesium hydroxide is obtained by electrolysis of aqueous caesium chloride solution: Caesium chloride is widely used in centrifugation in a technique known as isopycnic centrifugation . Centripetal and diffusive forces establish a density gradient that allow separation of mixtures on the basis of their molecular density. This technique allows separation of DNA of different densities (e.g. DNA fragments with differing A-T or G-C content). This application requires

2450-467: Was studied using conventional non-radioactive CsCl. Whereas conventional caesium chloride has a rather low toxicity to humans and animals, the radioactive form easily contaminates the environment due to the high solubility of CsCl in water. Spread of CsCl powder from a 93-gram container in 1987 in Goiânia , Brazil, resulted in one of the worst-ever radiation spill accidents killing four and directly affecting 249 people. The caesium chloride structure adopts

2500-430: Was used in isolation of caesium, contained about 0.17 mg/L of CsCl. None of these minerals are commercially important. On industrial scale, CsCl is produced from the mineral pollucite , which is powdered and treated with hydrochloric acid at elevated temperature. The extract is treated with antimony chloride , iodine monochloride , or cerium(IV) chloride to give the poorly soluble double salt, e.g.: Treatment of

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