As shown in the example below, this was executed by a transannular halide abstraction strategy through the reaction of the oxonium ion precursor (an organic halide) with the silver salt of the Krossing's anion Ag[Al(pftb) 4 ]•CH 2 Cl 2, generating the desired oxonium ion with simultaneous precipitation of inorganic silver halides. The resulting oxonium ions were characterized comprehensively by nuclear magnetic resonance spectroscopy at low temperature (–78 °C) with support from density functional theory computation.
oxoniumoxonium salttrialkyloxonium salts
Its original usage was as a chemical term, referring to bromine salts. Bromide has both literal and figurative meanings. The word originally derives from chemistry in which it can be used to describe a compound containing the element bromine, especially as a salt or bonded to an alkyl radical. Bromine was isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826) and the first appearance in print of "bromide" as a chemical term has been attributed to 1836. By the 1870s silver halides, such as silver bromide, were in commercial use as a photographic medium.
Before he could use hydrogen fluoride, Henri Moissan used fluoride salts with electrolysis. Thus on June 28, 1886 he performed his experiment in front of the Academie des Science to show his discovery of the new element fluorine. In the cost of trying to find elemental fluorine through electrolysis of fluoride salts, many chemists perished such as: George Gore, Pauline Louyet, Jerome Nickels. Electrolysis is the passing of a direct electric current through an ionic substance that is either molten or dissolved in a suitable solvent, producing chemical reactions at the electrodes and decomposition of the materials.
The systematic attribution of spectra to chemical elements began in the 1860s with the work of German physicist Gustav Kirchhoff and chemist Robert Bunsen. Bunsen and Kirchhoff applied the optical techniques of Fraunhofer, Bunsen's improved flame source and a highly systematic experimental procedure to a detailed examination of the spectra of chemical compounds. They established the linkage between chemical elements and their unique spectral patterns. In the process, they established the technique of analytical spectroscopy. In 1860, they published their findings on the spectra of eight elements and identified these elements' presence in several natural compounds.
The NRDC report conceded that "most waters contained no detectable bacteria, however, and the level of synthetic organic chemicals and inorganic chemicals of concern for which [they] were tested were either below detection limits or well below all applicable standards." Meanwhile, a report by the Drinking Water Research Foundation found that of all samples tested by NRDC, "federal FDA or EPA limits were allegedly exceeded only four times, twice for total coliforms and twice for fluorides." Studies show that the plastics used for bottles contain chemicals having estrogenic activity, even when they claim otherwise.
chemicalChemical changes in matterchemically
An example of a chemical change is the reaction between sodium and water to produce sodium hydroxide and hydrogen. So much energy is released that the hydrogen gas released spontaneously burns in the air. This is an example of a chemical change because the end products are chemically different from the substances before the chemical reaction. Chemists categorize chemical changes into three main classes: inorganic chemical changes, organic chemical changes and biochemical changes. Inorganic chemistry describes the reactions of elements and compounds that, in general, do not involve carbon. The changes typically take place in laboratories, or on a larger scale in heavy industries.
aprotic solventprotic solventaprotic
. * Autoprotolysis solvents display hydrogen bonding. solvents have an acidic hydrogen (although they may be very weak acids such as ethanol). solvents dissolve salts. cations by unshared free electron pairs. anions by hydrogen bonding. solvents that can accept hydrogen bonds. solvents that do not have acidic hydrogen. solvents that can dissolve salts. Loudon, G. Mark. Organic Chemistry 4th ed. New York: Oxford University Press. 2002. pg 317. https://pubchem.ncbi.nlm.nih.gov/compound/dimethyl_sulfoxide#section=Top. Dr.Paul.o.victory. Africaan's chemical press.2010.pg405.
Ceramic conservationceramic materialCeramics
In naturally occurring water, carbon dioxide is dissolved and can create a chemical reaction with minerals in clay bodies that may form calcium bicarbonate which is very soluble. Stagnant water is less damaging because the carbon dioxide is not exhausted. A common degradation issue in ceramics involves soluble salts. Soluble salts can either enter the clay body from the environment, for example from being buried underground for decades, or they are already naturally occurring due to the components of the materials or clay used. Non-archaeological objects, such as modern dishware, can acquire salts from normal use such as storing salt.
C 5 H 4 O 8 Methanetetracarboxylic acid
In chemistry, methanetetracarboxylate is a tetravalent anion with formula or C(COO − ) 4. It has four carboxylate groups attached to a central carbon atom; so it has the same carbon backbone as neopentane. It is an oxocarbon anion, that is, consists only of carbon and oxygen. The term is also used for any salt with that anion; or for any ester with the C(COO) 4 moiety. The salts and esters are relatively uncommon, and their uses appear to be limited to chemical research. The sodium salt Na 4 C(COO) 4 can be obtained by oxidation of pentaerythritol C(CH 2 OH) 4 with oxygen in sodium hydroxide solution at pH 10 and about 60 °C, in the presence of palladium as a catalyst.
Reed M. IzattIzatt
Christensen, a chemical engineer, founded a thermochemical institute at BYU to promote and facilitate interdisciplinary research. Izatt is a fellow of the American Association for the Advancement of Science (1982). He was the BYU Annual Faculty Lecture in 1970. Izatt received the Utah Award (1971) (Salt Lake Section, American Chemical Society); the Huffman Award (1983) (Calorimetry Conference); the American Chemical Society Separations Science and Technology Award (1996); the Utah Governor's Medal for Science and Technology (1990); and the First Annual Alumni Achievement Award (2001) (Utah State University Department of Chemistry and Biochemistry). Reed M.
Dr. PlotPlotDr. Robert Plot
Another implication of his success was his appointment as the first keeper of the newly established Ashmolean Museum in 1683, as well as his simultaneous appointment as the first professor of chemistry in the new well-equipped laboratory housed within the museum. In the field of chemistry he searched for a universal solvent that could be obtained from wine spirits, and believed that alchemy was necessary for medicine. In 1684, Plot published De origine fontium, a treatise on the source of springs, which he attributed to underground channels originating from the sea.
More recent evidence for liquid water comes from the finding of the mineral gypsum on the surface by NASA's Mars rover Opportunity in December 2011. It is estimated that the amount of water in the upper mantle of Mars, represented by hydroxyl ions contained within the minerals of Mars's geology, is equal to or greater than that of Earth at 50–300 parts per million of water, which is enough to cover the entire planet to a depth of 200 - 1000 m. In 2005, radar data revealed the presence of large quantities of water ice at the poles and at mid-latitudes. The Mars rover Spirit sampled chemical compounds containing water molecules in March 2007.
ammonium sulphate(NH 4 ) 2 SO 4 ammonium sulphate solution
The heat of reaction evaporates all water present in the system, forming a powdery salt. Approximately 6000M tons were produced in 1981. Ammonium sulfate also is manufactured from gypsum (CaSO 4 ·2H 2 O). Finely divided gypsum is added to an ammonium carbonate solution. Calcium carbonate precipitates as a solid, leaving ammonium sulfate in the solution. : (NH 4 ) 2 CO 3 + CaSO 4 → (NH 4 ) 2 SO 4 + CaCO 3 Ammonium sulfate occurs naturally as the rare mineral mascagnite in volcanic fumaroles and due to coal fires on some dumps. Ammonium sulfate becomes ferroelectric at temperatures below -49.5 °C.
Straits of GibraltarGibraltar Straitstraits
Around 5.9 million years ago, the connection between the Mediterranean Sea and the Atlantic Ocean along the Betic and Rifan Corridor was progressively restricted until its total closure, effectively causing the salinity of the Mediterranean to rise periodically within the gypsum and salt deposition range, during what is known as the Messinian salinity crisis. In this water chemistry environment, dissolved mineral concentrations, temperature and stilled water currents combined and occurred regularly to precipitate many mineral salts in layers on the seabed. The resultant accumulation of various huge salt and mineral deposits about the Mediterranean basin are directly linked to this era.
Thus, despite the problems associated with the studies on properties and activities of ions in various chemical and biological systems, this research field is among the most urgent ones. Of special interest are ion-abundant liquid media (such as ionic liquids, molten salts, liquid electrolytes, etc.), which represent “liquid ions” with excellent tunable properties for different applications. The systems are famous for their ability to solvent-solute self-organization phenomena and are often employed in chemistry, biochemistry and pharmaceutical research. One of the most important features of ion-abundant liquid media is their huge potential to be fine-tuned.
agricultural fertiliserHistory of fertiliser
Johann Friedrich Mayer (1719–1798) was the first to present to the world a series of experiments upon it the relation of gypsum to agriculture, and many chemists have followed him in the 19th century. Early 19th century however a great variety of opinion remained with regard to its mode of operation, for example: Mayer also promote new regimes of crop rotation. Chemist Justus von Liebig (1803–1873) contributed greatly to the advancement in the understanding of plant nutrition. His influential works first denounced the vitalist theory of humus, arguing first the importance of ammonia, and later promoting the importance of inorganic minerals to plant nutrition.
tobaccoN. tabacumCultivated Tobacco
In 1851, the Belgian chemist Jean Stas documented the use of tobacco extract as a murder poison. The Belgian count Hippolyte Visart de Bocarmé had poisoned his brother-in-law with tobacco leaf extract in order to acquire some urgently needed money. This was the first exact proof of alkaloids in forensic medicine. N. tabacum is a native of tropical and subtropical America but it is now commercially cultivated worldwide. Other varieties are cultivated as ornamental plants or grow as a weed. N. tabacum is sensitive to temperature, air, ground humidity and the type of land.
FresnelAugustin FresnelAugustin Jean Fresnel
That difference may explain why leading chemists, who learned of his discovery through his uncle Léonor, eventually thought it uneconomic. About 1812, Fresnel was sent to Nyons, in the southern département of Drôme, to assist with the imperial highway that was to connect Spain and Italy. It is from Nyons that we have the first evidence of his interest in optics. On 15 May 1814, while work was slack due to Napoleon's defeat, Fresnel wrote a "P.S." to his brother Léonor, saying in part: "I would also like to have papers that might tell me about the discoveries of French physicists on the polarization of light.
For advice on assembling the laboratory's Chemistry Division, Compton, a physicist, turned to Herbert McCoy, who had considerable experience with isotopes and radioactive elements. McCoy recommended Frank Spedding from Iowa State College in Ames, Iowa, as an expert on the rare-earth elements, which were chemically similar to the actinide series that included uranium and plutonium. Compton asked Spedding to become the head of the Metallurgical Laboratory's Chemistry Division. Due to a lack of space at the University of Chicago, Spedding proposed to organize part of the Chemistry Division at Iowa State College, where he had colleagues who were willing to help.
Messinian EventMessinian desiccationstays dry
The first drilling of the Messinian salt at the deeper parts of the Mediterranean Sea came in the summer of 1970, when geologists aboard the Glomar Challenger brought up drill cores containing arroyo gravels and red and green floodplain silts; and gypsum, anhydrite, rock salt, and various other evaporite minerals that often form from drying of brine or seawater, including in a few places potash, left where the last bitter, mineral-rich waters dried up.
The article is based on the book, Inventing Polymer Science: Staudinger, Carothers, and the Emergence of Macromolecular Chemistry by Yasu Furukawa.
J. F. HellerJohann Heller
Johann Florian Heller (4 May 1813 – 21 November 1871) was an Austrian chemist who was one of the founders of clinical chemistry. Heller was born in Vienna, Austria. He studied chemistry in Prague and later with Liebig and Wöhler at Giessen. During those studies he characterized rhodizonic acid and its potassium salt (1837). In 1844 Heller established a laboratory of pathological chemistry in Vienna's General Hospital, but his appointment as head of the lab was delayed until 1855 because some of the faculty thought that the position should be occupied by a medical doctor.
Michael Denk's research ranges over several areas of organic and inorganic chemistry, including carbenes and their analogs, carbenium salts, silicon, germanium, and tin chemistry, volatile metal complexes, inorganic photochemistry, ionic liquids, and more; as well as applications such as chemical vapor deposition processes, semiconductors, thin films, etc. He has recently established the reality of the Wanzlick equilibrium, which had been put in doubt by experiments of D. Lemal and others.
Johann Friedrich Wilhelm Adolf von BaeyerBaeyervon Baeyer
In 1905 he was awarded the Nobel Prize in Chemistry "in recognition of his services in the advancement of organic chemistry and the chemical industry, through his work on organic dyes and hydroaromatic compounds", and he continued in full active work as one of the best-known teachers in the world of organic chemistry up to within a year of his death. Since 1911, is established the which is awarded annually. His name is reflected in various "name reactions" as the Baeyer-Villiger Oxidation and Baeyer's reagent. There is also the Von Baeyer nomenclature in structural chemistry and Baeyer strain theory (which granted him the Nobel prize) of alicyclic compounds.
alcoholssecondary alcoholtertiary alcohol
Alcohol distillation was known to Islamic chemists as early as the eighth century. The Arab chemist, al-Kindi, unambiguously described the distillation of wine in a treatise titled as "The Book of the chemistry of Perfume and Distillations". The Persian physician, alchemist, polymath and philosopher Rhazes (854 CE – 925 CE) is credited with the discovery of ethanol. The word "alcohol" is from the Arabic kohl, a powder used as an eyeliner. Al- is the Arabic definite article, equivalent to the in English. Alcohol was originally used for the very fine powder produced by the sublimation of the natural mineral stibnite to form antimony trisulfide.