query: What is the chemical formula for sulphur dioxide?

title: Sulfur dioxide

text: 2011 systematic review concluded that exposure to sulfur dioxide is associated with preterm birth. In the United States, the Center for Science in the Public Interest lists the two food preservatives, sulfur dioxide and sodium bisulfite, as being safe for human consumption except for certain asthmatic individuals who may be sensitive to them, especially in large amounts. Symptoms of sensitivity to sulfiting agents, including sulfur dioxide, manifest as potentially life-threatening trouble breathing within minutes of ingestion. Sulfur dioxide Sulfur dioxide (also sulphur dioxide in British English) is the chemical compound with the formula . It is a toxic gas with

title: Sulfur dioxide

text: Sulfur dioxide Sulfur dioxide (also sulphur dioxide in British English) is the chemical compound with the formula . It is a toxic gas with a burnt match smell. It is released naturally by volcanic activity and is produced as a by-product of the burning of fossil fuels contaminated with sulfur compounds and copper extraction. SO is a bent molecule with "C" symmetry point group. A valence bond theory approach considering just "s" and "p" orbitals would describe the bonding in terms of resonance between two resonance structures. The sulfur–oxygen bond has a bond order of 1.5. There is support for

title: Bromine dioxide

text: Bromine dioxide Bromine dioxide is the chemical compound composed of bromine and oxygen with the formula BrO. It forms unstable yellow to yellow-orange crystals. It was first isolated by R. Schwarz and M. Schmeißer in 1937 and is hypothesized to be important in the atmospheric reaction of bromine with ozone. It is similar to chlorine dioxide, the dioxide of its halogen neighbor one period higher on the periodic table. Bromine dioxide is formed when an electric current is passed through a mixture of bromine and oxygen gases at low temperature and pressure. Bromine dioxide can also be formed by the

title: Niobium dioxide

text: with baddeleyite-related structure. NbO is insoluble in water and is a powerful reducing agent, reducing carbon dioxide to carbon and sulfur dioxide to sulfur. In an industrial process for the production of niobium metal , NbO is produced as an intermediate, by the hydrogen reduction of NbO. The NbO is subsequently reacted with magnesium vapour to produce niobium metal. Niobium dioxide Niobium dioxide, is the chemical compound with the formula NbO. It is a bluish black non-stoichiometric solid with a composition range of NbO-NbO It can be prepared by reacting NbO with H at 800–1350 °C. An alternative method is

title: Bromine dioxide

text: treatment of bromine gas with ozone in trichlorofluoromethane at −50 °C. When mixed with a base, bromine dioxide gives the bromide and bromate anions: Bromine dioxide Bromine dioxide is the chemical compound composed of bromine and oxygen with the formula BrO. It forms unstable yellow to yellow-orange crystals. It was first isolated by R. Schwarz and M. Schmeißer in 1937 and is hypothesized to be important in the atmospheric reaction of bromine with ozone. It is similar to chlorine dioxide, the dioxide of its halogen neighbor one period higher on the periodic table. Bromine dioxide is formed when an electric

title: Nitrogen dioxide

text: Nitrogen dioxide Nitrogen dioxide is the chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year which is used primary in production of fertilizers. At higher temperatures it is a reddish-brown gas that has a characteristic sharp, biting odor and is a prominent air pollutant. Nitrogen dioxide is a paramagnetic, bent molecule with C point group symmetry. Nitrogen dioxide is a reddish-brown gas above with a pungent, acrid odor, becomes a yellowish-brown liquid below , and converts to

title: Selenium dioxide

text: Selenium dioxide Selenium dioxide is the chemical compound with the formula SeO. This colorless solid is one of the most frequently encountered compounds of selenium. Solid SeO is a one-dimensional polymer, the chain consisting of alternating selenium and oxygen atoms. Each Se atom is pyramidal and bears a terminal oxide group. The bridging Se-O bond lengths are 179 pm and the terminal Se-O distance is 162 pm. The relative stereochemistry at Se alternates along the polymer chain (syndiotactic). In the gas phase selenium dioxide is present as dimers and other oligomeric species, at higher temperatures it is monomeric. The monomeric

title: Nitrogen dioxide

text: NO exposure concentrations near roadways are of particular concern for susceptible individuals, including asthmatics, children, and the elderly. For limits in other countries see the table in the "Ambient air quality criteria" article. Nitrogen dioxide Nitrogen dioxide is the chemical compound with the formula . It is one of several nitrogen oxides. is an intermediate in the industrial synthesis of nitric acid, millions of tons of which are produced each year which is used primary in production of fertilizers. At higher temperatures it is a reddish-brown gas that has a characteristic sharp, biting odor and is a prominent air pollutant.

title: Molybdenum dioxide

text: deposited on graphite. Molybdenum oxide has also been suggested as possible anode material for Li-ion batteries. The mineralogical form of this compound is called tugarinovite, and is only very rarely found. Molybdenum dioxide Molybdenum dioxide is the chemical compound with the formula MoO. It is a violet-colored solid and is a metallic conductor. It crystallizes in a monoclinic cell, and has a distorted rutile, (TiO) crystal structure. In TiO the oxide anions are close packed and titanium atoms occupy half of the octahedral interstices (holes). In MoO the octahedra are distorted, the Mo atoms are off-centre, leading to alternating short

title: Molybdenum dioxide

text: Molybdenum dioxide Molybdenum dioxide is the chemical compound with the formula MoO. It is a violet-colored solid and is a metallic conductor. It crystallizes in a monoclinic cell, and has a distorted rutile, (TiO) crystal structure. In TiO the oxide anions are close packed and titanium atoms occupy half of the octahedral interstices (holes). In MoO the octahedra are distorted, the Mo atoms are off-centre, leading to alternating short and long Mo – Mo distances and Mo-Mo bonding. The short Mo – Mo distance is 251 pm which is less than the Mo – Mo distance in the metal, 272.5

title: Niobium dioxide

text: Niobium dioxide Niobium dioxide, is the chemical compound with the formula NbO. It is a bluish black non-stoichiometric solid with a composition range of NbO-NbO It can be prepared by reacting NbO with H at 800–1350 °C. An alternative method is reaction of NbO with Nb powder at 1100 °C. The room temperature form NbO has a tetragonal, rutile-like structure with short Nb-Nb distances indicating Nb-Nb bonding. High temp form also has a rutile-like structure with short Nb-Nb distances. Two high pressure phases have been reported one with a rutile-like structure, again with short Nb-Nb distances, and a higher pressure

title: Tungsten dichloride dioxide

text: Tungsten dichloride dioxide Tungsten dichloride dioxide is the chemical compound with the formula WOCl. It is a yellow-colored solid. It is used as a precursor to other tungsten compounds. Like other tungsten halides, WOCl is sensitive to moisture, undergoing hydrolysis. WOCl is prepared by ligand redistribution reaction from tungsten trioxide and tungsten hexachloride: Using a two-zone tube furnace, a vacuum-sealed tube containing these solids is heated to 350 °C. The yellow product sublimes to the cooler end of the reaction tube. No redox occurs in this process. An alternative route highlights the oxophilicity of tungsten: This reaction, like the preceding

title: Tungsten dichloride dioxide

text: of the inorganic solid, but are generated in situ from WOCl. Tungsten dichloride dioxide Tungsten dichloride dioxide is the chemical compound with the formula WOCl. It is a yellow-colored solid. It is used as a precursor to other tungsten compounds. Like other tungsten halides, WOCl is sensitive to moisture, undergoing hydrolysis. WOCl is prepared by ligand redistribution reaction from tungsten trioxide and tungsten hexachloride: Using a two-zone tube furnace, a vacuum-sealed tube containing these solids is heated to 350 °C. The yellow product sublimes to the cooler end of the reaction tube. No redox occurs in this process. An alternative

title: Empirical formula

text: Empirical formula In chemistry, the empirical formula of a chemical compound is the simplest positive integer ratio of atoms present in a compound. A simple example of this concept is that the empirical formula of sulphur monoxide, or SO, would simply be SO, as is the empirical formula of disulfur dioxide, SO. This means that sulfur monoxide and disulfur dioxide, both compounds of sulfur and oxygen, will have the same empirical formula. However, their chemical formulas, which express the number of atoms in each molecule of a chemical compound, may not be the same. An empirical formula makes no mention

title: Chlorine dioxide

text: Chlorine dioxide Chlorine dioxide is a chemical compound with the formula ClO. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching. Chlorine dioxide is a neutral chlorine compound. It is very different from elemental chlorine, both in its chemical structure and in its behavior. One of the most important qualities of chlorine dioxide is its high water solubility, especially in cold water. Chlorine dioxide does not hydrolyze when it enters water; it remains a dissolved gas

title: Chlorine dioxide

text: has received numerous reports of nausea, diarrhea, severe vomiting, and life-threatening low blood pressure caused by dehydration. Chlorine dioxide Chlorine dioxide is a chemical compound with the formula ClO. This yellowish-green gas crystallizes as bright orange crystals at −59 °C. As one of several oxides of chlorine, it is a potent and useful oxidizing agent used in water treatment and in bleaching. Chlorine dioxide is a neutral chlorine compound. It is very different from elemental chlorine, both in its chemical structure and in its behavior. One of the most important qualities of chlorine dioxide is its high water solubility, especially

title: Chemical formula

text: of chemical formulas. For example, alcohols may be represented by the formula CHOH ("n" ≥ 1), giving the homologs methanol, ethanol, propanol for "n"=1–3. The Hill system (or Hill notation) is a system of writing empirical chemical formulas, molecular chemical formulas and components of a condensed formula such that the number of carbon atoms in a molecule is indicated first, the number of hydrogen atoms next, and then the number of all other chemical elements subsequently, in alphabetical order of the chemical symbols. When the formula contains no carbon, all the elements, including hydrogen, are listed alphabetically. By sorting formulas

title: Chemical cycling

text: Recent studies indicate a hydrological cycle of water-ammonia vastly different to the type operating on terrestrial planets like Earth and also a cycle of hydrogen sulfide. Significant chemical cycles exist on Jupiter's moons. Recent evidence points to Europa possessing several active cycles, most notably a water cycle. Other studies suggest an oxygen and radiation induced carbon dioxide cycle. Io and Europa, appear to have radiolytic sulphur cycles involving their lithospheres. In addition, Europa is thought to have a sulfur dioxide cycle. In addition, the Io plasma torus contributes to a sulphur cycle on Jupiter and Ganymede. Studies also imply active

title: Tetracarbon dioxide

text: Tetracarbon dioxide Tetracarbon dioxide is an oxide of carbon, a chemical compound of carbon and oxygen, with chemical formula CO or O=C=C=C=C=O. It can be regarded as butatriene dione, the double ketone of butatriene — more precisely 1,2,3-butatriene-1,4-dione. Butatriene dione is the fourth member of the family of linear carbon dioxides O(=C)=O, that includes carbon dioxide CO or O=C=O, ethylene dione CO or O=C=C=O, carbon suboxide CO or O=C=C=C=O, pentacarbon dioxide CO or O=C=C=C=C=C=O, and so on. The compound was obtained in 1990 by Maier and others, by flash vacuum pyrolysis of cyclic azaketones in a frozen argon matrix. It

title: Chemical cycling

text: significant being a strong carbon dioxide cycle. The lack of a complete carbon cycle including a geochemical carbon cycle, for example, is thought to be a cause of its runaway greenhouse effect, due to the lack of a substantial carbon sink. Sulphur cycles including sulphur oxide cycles also occur, sulphur oxide in the upper atmosphere and results in the presence of sulfuric acid in turn returns to oxides through photolysis. Indications also suggest an ozone cycle on Venus similar to that of Earth's. A number of different types of chemical cycles geochemical cycles occur on Earth. Biogeochemical cycles play an

title: Chemical formula

text: Chemical formula The connectivity of a molecule often has a strong influence on its physical and chemical properties and behavior. Two molecules composed of the same numbers of the same types of atoms (i.e. a pair of isomers) might have completely different chemical and/or physical properties if the atoms are connected differently or in different positions. In such cases, a structural formula is useful, as it illustrates which atoms are bonded to which other ones. From the connectivity, it is often possible to deduce the approximate shape of the molecule. A condensed chemical formula may represent the types and spatial

title: Chemical formula

text: formulas. See IUPAC nomenclature of organic chemistry and IUPAC nomenclature of inorganic chemistry 2005 for examples. In addition, linear naming systems such as International Chemical Identifier (InChI) allow a computer to construct a structural formula, and simplified molecular-input line-entry system (SMILES) allows a more human-readable ASCII input. However, all these nomenclature systems go beyond the standards of chemical formulas, and technically are chemical naming systems, not formula systems. For polymers in condensed chemical formulas, parentheses are placed around the repeating unit. For example, a hydrocarbon molecule that is described as CH(CH)CH, is a molecule with fifty repeating units. If the

title: Chemical formula

text: according to the number of atoms of each element present in the formula according to these rules, with differences in earlier elements or numbers being treated as more significant than differences in any later element or number—like sorting text strings into lexicographical order—it is possible to collate chemical formulas into what is known as Hill system order. The Hill system was first published by Edwin A. Hill of the United States Patent and Trademark Office in 1900. It is the most commonly used system in chemical databases and printed indexes to sort lists of compounds. A list of formulas in

title: Chemical formula

text: on), and the visual aspects suggesting the structure of an endohedral fullerene. Chemical formulas most often use integers for each element. However, there is a class of compounds, called non-stoichiometric compounds, that cannot be represented by small integers. Such a formula might be written using decimal fractions, as in FeO, or it might include a variable part represented by a letter, as in FeO, where x is normally much less than 1. A chemical formula used for a series of compounds that differ from each other by a constant unit is called a "general formula". It generates a homologous series

title: Carbon dioxide

text: Carbon dioxide Carbon dioxide (chemical formula ) is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth's atmosphere as a trace gas. The current concentration is about 0.04% (410 ppm) by volume, having risen from pre-industrial levels of 280 ppm. Natural sources include volcanoes, hot springs and geysers, and it is freed from carbonate rocks by dissolution in water and acids. Because carbon dioxide is soluble in water, it occurs naturally in groundwater, rivers and lakes,

title: Chemical formula

text: arrangement of bonds in a simple chemical substance, though it does not necessarily specify isomers or complex structures. For example, ethane consists of two carbon atoms single-bonded to each other, with each carbon atom having three hydrogen atoms bonded to it. Its chemical formula can be rendered as CHCH. In ethylene there is a double bond between the carbon atoms (and thus each carbon only has two hydrogens), therefore the chemical formula may be written: CHCH, and the fact that there is a double bond between the carbons is implicit because carbon has a valence of four. However, a more

title: Empirical formula

text: of the arrangement or number of atoms. It is standard for many ionic compounds, like calcium chloride (CaCl), and for macromolecules, such as silicon dioxide (SiO). The molecular formula, on the other hand, shows the number of each type of atom in a molecule. The structural formula shows the arrangement of the molecule. It is also possible for different types of compounds to have equal empirical formulas. Samples are analyzed in specific elemental analysis tests to determine what percent of a particular element the sample is composed of. A chemical analysis of a sample of methyl acetate provides the following

title: Carbon dioxide

text: the content of arterial blood may be lowered to 10–20 mm Hg (the oxygen content of the blood is little affected), and the respiratory drive is diminished. This is why one can hold one's breath longer after hyperventilating than without hyperventilating. This carries the risk that unconsciousness may result before the need to breathe becomes overwhelming, which is why hyperventilation is particularly dangerous before free diving. Carbon dioxide Carbon dioxide (chemical formula ) is a colorless gas with a density about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two

title: Tetracarbon dioxide

text: was also obtained in the same year by Sülzle and Schwartz through impact ionization of ((CH-)(CO)(=O)=) in the gas phase. Although theoretical studies indicated that the even-numbered members of the O(=C)=O family should be inherently unstable, CO is indefinitely stable in the matrix, but is decomposed by light into tricarbon monoxide CO and carbon monoxide CO. It has a triplet ground state. Tetracarbon dioxide Tetracarbon dioxide is an oxide of carbon, a chemical compound of carbon and oxygen, with chemical formula CO or O=C=C=C=C=O. It can be regarded as butatriene dione, the double ketone of butatriene — more precisely 1,2,3-butatriene-1,4-dione.

title: Polonium dioxide

text: Polonium dioxide Polonium dioxide (also known as polonium(IV) oxide) is a chemical compound with the formula PoO. It is one of three oxides of polonium, the other two being polonium monoxide (PoO) and polonium trioxide (PoO). It is a pale yellow crystalline solid at room temperature. Under lowered pressure (such as a vacuum), it decomposes into elemental polonium and oxygen at 500 °C. It is the most stable oxide of polonium and is an interchalcogen. At room temperature, polonium dioxide has a face-centered cubic (fluorite) crystal structure; upon heating to high temperatures, it crystallises in the tetragonal crystal system. The

title: Titanium dioxide

text: Titanium dioxide Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. Generally, it is sourced from ilmenite, rutile and anatase. It has a wide range of applications, including paint, sunscreen and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million metric tons. It has been estimated that titanium dioxide is used in two-thirds of all pigments, and the oxide has been valued

title: Titanium dioxide

text: S-IVB stage from Apollo 12 and not an asteroid. Titanium dioxide Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturally occurring oxide of titanium, chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. Generally, it is sourced from ilmenite, rutile and anatase. It has a wide range of applications, including paint, sunscreen and food coloring. When used as a food coloring, it has E number E171. World production in 2014 exceeded 9 million metric tons. It has been estimated that titanium dioxide is used in two-thirds

title: Chemical cycling

text: important role in sustaining the biosphere. Notable active chemical cycles on Earth include: Other chemical cycles include hydrogen peroxide. Recent evidence suggests that similar chemical cycles to Earth's occur on a lesser scale on Mars, facilitated by the thin atmosphere, including carbon dioxide (and possibly carbon), water, sulphur, methane, oxygen, ozone, and nitrogen cycles. Many studies point to significantly more active chemical cycles on Mars in the past, however the faint young Sun paradox has proved problematic in determining chemical cycles involved in early climate models of the planet. Jupiter, like all the gas giants, has an atmospheric methane cycle.

title: Lead dioxide

text: Lead dioxide Lead(IV) oxide, commonly called lead dioxide or plumbic oxide or anhydrous plumbic acid (sometimes wrongly called lead peroxide,) is a chemical compound with the formula PbO. It is an oxide where lead is in an oxidation state of +4; bond type is predominantly covalent. It is an odorless dark-brown crystalline powder which is nearly insoluble in water. It exists in two crystalline forms. The alpha phase has orthorhombic symmetry; it was first synthesized in 1941 and was identified in nature as a rare mineral scrutinyite in 1988. The more common tetragonal beta phase was first identified as the

title: Silicon dioxide

text: Silicon dioxide Silicon dioxide, also known as silica, silicic acid or silicic acid anydride is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as synthetic product. Notable examples include fused quartz, fumed silica, silica gel, and aerogels. It is used in structural materials, microelectronics (as an electrical insulator), and as components in the

title: Silicon dioxide

text: material, exists in many crystalline forms. These forms are called polymorphs. Silicon dioxide Silicon dioxide, also known as silica, silicic acid or silicic acid anydride is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as synthetic product. Notable examples include fused quartz, fumed silica, silica gel, and aerogels. It is used in structural

title: Polonium dioxide

text: out. Gloves made of natural rubber do not provide sufficient protection against the radiation from polonium; surgical gloves are necessary. Neoprene gloves shield radiation from polonium better than natural rubber. Polonium dioxide Polonium dioxide (also known as polonium(IV) oxide) is a chemical compound with the formula PoO. It is one of three oxides of polonium, the other two being polonium monoxide (PoO) and polonium trioxide (PoO). It is a pale yellow crystalline solid at room temperature. Under lowered pressure (such as a vacuum), it decomposes into elemental polonium and oxygen at 500 °C. It is the most stable oxide of

title: Germanium dioxide

text: Germanium dioxide Germanium dioxide, also called germanium oxide, germania, and salt of germanium, is an inorganic compound with the chemical formula GeO. It is the main commercial source of germanium. It also forms as a passivation layer on pure germanium in contact with atmospheric oxygen. The two predominant polymorphs of GeO are hexagonal and tetragonal. Hexagonal GeO has the same structure as β-quartz, with germanium having coordination number 4. Tetragonal GeO (the mineral argutite) has the rutile-like structure seen in stishovite. In this motif, germanium has the coordination number 6. An amorphous (glassy) form of GeO is similar to fused

title: Germanium dioxide

text: supplement in some questionable dietary supplements and "miracle cures". High doses of these resulted in several cases of germanium poisonings. Germanium dioxide Germanium dioxide, also called germanium oxide, germania, and salt of germanium, is an inorganic compound with the chemical formula GeO. It is the main commercial source of germanium. It also forms as a passivation layer on pure germanium in contact with atmospheric oxygen. The two predominant polymorphs of GeO are hexagonal and tetragonal. Hexagonal GeO has the same structure as β-quartz, with germanium having coordination number 4. Tetragonal GeO (the mineral argutite) has the rutile-like structure seen in

title: Osmium dioxide

text: Osmium dioxide Osmium dioxide is an inorganic compound with the formula OsO. It exists as brown to black crystalline powder, but single crystals are golden and exhibit metallic conductivity. The compound crystallizes in the rutile structural motif, i.e. the connectivity is very similar to that in the mineral rutile. OsO can be obtained by the reaction of osmium with a variety of oxidizing agents, including, sodium chlorate, osmium tetroxide, and nitric oxide at about 600 °C. Using chemical transport, one can obtain large crystals of OsO, sized up to 7x5x3 mm. Single crystals show metallic resistivity of ~15 μΩ cm.

title: Silicon dioxide

text: discharge. Dimeric silicon dioxide, (SiO) has been prepared by reacting O with matrix isolated dimeric silicon monoxide, (SiO). In dimeric silicon dioxide there are two oxygen atoms bridging between the silicon atoms with an Si-O-Si angle of 94° and bond length of 164.6 pm and the terminal Si-O bond length is 150.2 pm. The Si-O bond length is 148.3 pm, which compares with the length of 161 pm in α-quartz. The bond energy is estimated at 621.7 kJ/mol. Silica with the chemical formula is most commonly found in nature as quartz, which comprises more than 10% by mass of the

title: Chemical formula

text: Hill system order is arranged alphabetically, as above, with single-letter elements coming before two-letter symbols when the symbols begin with the same letter (so "B" comes before "Be", which comes before "Br"). The following example formulae are written using the Hill system, and listed in Hill order: Chemical formula The connectivity of a molecule often has a strong influence on its physical and chemical properties and behavior. Two molecules composed of the same numbers of the same types of atoms (i.e. a pair of isomers) might have completely different chemical and/or physical properties if the atoms are connected differently or

title: Chemical formula

text: as Cs[BH]. Parentheses ( ) can be nested inside brackets to indicate a repeating unit, as in [Co(NH)]Cl. Here, (NH) indicates that the ion contains six NH groups bonded to cobalt, and [ ] encloses the entire formula of the ion with charge +3. This is strictly optional; a chemical formula is valid with or without ionization information, and Hexamminecobalt(III) chloride may be written as [Co(NH)]Cl or [Co(NH)]Cl. Brackets, like parentheses, behave in chemistry as they do in mathematics, grouping terms together they are not specifically employed only for ionization states. In the latter case here, the parentheses indicate 6

title: Chemical formula

text: a different connectivity from other molecules that can be formed using the same atoms in the same proportions (isomers). The formula (CH)CH implies a central carbon atom connected to one hydrogen atom and three CH groups. The same number of atoms of each element (10 hydrogens and 4 carbons, or CH) may be used to make a straight chain molecule, "n"-butane: CHCHCHCH. In any given chemical compound, the elements always combine in the same proportion with each other. This is the law of constant composition. The law of constant composition says that, in any particular chemical compound, all samples of

title: Carbon dioxide (data page)

text: Carbon dioxide (data page) This page provides supplementary chemical data on carbon dioxide. The handling of this chemical may incur notable safety precautions. It is highly recommended that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source such as SIRI, and follow its directions. MSDS for solid carbon dioxide is available from Pacific Dry Ice, inc. Table data obtained from "CRC Handbook of Chemistry and Physics" 44th ed. Annotation "(s)" indicates equilibrium temperature of vapor over solid. Otherwise temperature is equilibrium of vapor over liquid. For kPa values, where datum is whole numbers of atmospheres

title: Chemical formula

text: that compound will be made up of the same elements in the same proportion or ratio. For example, any water molecule is always made up of two hydrogen atoms and one oxygen atom in a 2:1 ratio. If we look at the relative masses of oxygen and hydrogen in a water molecule, we see that 94% of the mass of a water molecule is accounted for by oxygen and the remaining 6% is the mass of hydrogen. This mass proportion will be the same for any water molecule. The alkene called but-2-ene has two isomers, which the chemical formula CHCH=CHCH

title: Chemical formula

text: groups all of the same shape, bonded to another group of size 1 (the cobalt atom), and then the entire bundle, as a group, is bonded to 3 chlorine atoms. In the former case, it is clearer that the bond connecting the chlorines is ionic, rather than covalent. Although isotopes are more relevant to nuclear chemistry or stable isotope chemistry than to conventional chemistry, different isotopes may be indicated with a prefixed superscript in a chemical formula. For example, the phosphate ion containing radioactive phosphorus-32 is [PO]. Also a study involving stable isotope ratios might include the molecule OO. A

title: Carbon dioxide (data page)

text: °C and below, which are taken from "Lange's Handbook of Chemistry", 10th ed. page 1463. Except where noted otherwise, data relate to standard ambient temperature and pressure. Carbon dioxide (data page) This page provides supplementary chemical data on carbon dioxide. The handling of this chemical may incur notable safety precautions. It is highly recommended that you seek the Material Safety Datasheet (MSDS) for this chemical from a reliable source such as SIRI, and follow its directions. MSDS for solid carbon dioxide is available from Pacific Dry Ice, inc. Table data obtained from "CRC Handbook of Chemistry and Physics" 44th ed.

title: Manganese dioxide

text: silver or barium. is often called Hollandite, after a closely related mineral. Naturally occurring manganese dioxide contains impurities and a considerable amount of manganese(III) oxide. Only a limited number of deposits contain the γ modification in purity sufficient for the battery industry. Production of batteries and ferrite (two of the primary uses of manganese dioxide) requires high purity manganese dioxide. Batteries require "electrolytic manganese dioxide" while ferrites require "chemical manganese dioxide". One method starts with natural manganese dioxide and converts it using dinitrogen tetroxide and water to a manganese(II) nitrate solution. Evaporation of the water, leaves the crystalline nitrate salt.

title: Thorium dioxide

text: uranium dioxide fuel pellets, because of its higher thermal conductivity (lower operating temperature), considerably higher melting point, and chemical stability (does not oxidize in the presence of water/oxygen, unlike uranium dioxide). Thorium dioxide can be turned into a nuclear fuel by breeding it into uranium-233 (see below and refer to the article on thorium for more information on this). The high thermal stability of thorium dioxide allows applications in flame spraying and high-temperature ceramics. Thorium dioxide is used as a stabilizer in tungsten electrodes in TIG welding, electron tubes, and aircraft engines. As an alloy, thoriated tungsten metal is not

title: Carbon dioxide

text: Most of the remaining 50–55% is methane. Carbon dioxide is used by the food industry, the oil industry, and the chemical industry. The compound has varied commercial uses but one of its greatest use as a chemical is in the production of carbonated beverages; it provides the sparkle in carbonated beverages such as soda water, beer and sparkling wine. In the chemical industry, carbon dioxide is mainly consumed as an ingredient in the production of urea, with a smaller fraction being used to produce methanol and a range of other products, such as metal carbonates and bicarbonates. Some carboxylic acid

title: Carbon dioxide

text: Organization standards also recognize carbon dioxide systems for fire protection of ship holds and engine rooms. Carbon dioxide based fire protection systems have been linked to several deaths, because it can cause suffocation in sufficiently high concentrations. A review of systems identified 51 incidents between 1975 and the date of the report (2000), causing 72 deaths and 145 injuries. Liquid carbon dioxide is a good solvent for many lipophilic organic compounds and is used to remove caffeine from coffee. Carbon dioxide has attracted attention in the pharmaceutical and other chemical processing industries as a less toxic alternative to more traditional

title: Manganese dioxide

text: Otherwise, the applications of are numerous, being applicable to many kinds of reactions including amine oxidation, aromatization, oxidative coupling, and thiol oxidation. Chronic exposures to contaminated air with manganese dioxide particles can cause manganism. is classed as a cumulative neurotoxin according to the MSDS for Manganese Dioxide. Manganese dioxide Manganese(IV) oxide is the inorganic compound with the formula . This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for is for dry-cell batteries, such as the alkaline battery and the zinc-carbon battery.

title: Silicon dioxide

text: of the product are affected by catalysts, but the idealized equation is: Being highly stable, silicon dioxide arises from many methods. Conceptually simple, but of little practical value, combustion of silane gives silicon dioxide. This reaction is analogous to the combustion of methane: However the chemical vapor deposition of silicon dioxide onto crystal surface from silane had been used using nitrogen as a carrier gas at 200-500C. Silica is converted to silicon by reduction with carbon. Fluorine reacts with silicon dioxide to form SiF and O whereas the other halogen gases (Cl, Br, I) are essentially unreactive. Silicon dioxide is

title: Carbon dioxide

text: US and Australia and New Zealand (listed by its INS number 290). A candy called Pop Rocks is pressurized with carbon dioxide gas at about 4 x 10 Pa (40 bar, 580 psi). When placed in the mouth, it dissolves (just like other hard candy) and releases the gas bubbles with an audible pop. Leavening agents cause dough to rise by producing carbon dioxide. Baker's yeast produces carbon dioxide by fermentation of sugars within the dough, while chemical leaveners such as baking powder and baking soda release carbon dioxide when heated or if exposed to acids. Carbon dioxide is used

title: Lead dioxide

text: is an amphoteric compound with prevalent acidic properties. It dissolves in strong bases to form the hydroxyplumbate ion, [Pb(OH)]: It also reacts with basic oxides in the melt, yielding orthoplumbates M[PbO]. Because of the instability of its Pb cation, lead dioxide reacts with hot acids, converting to the more stable Pb state and liberating oxygen: However these reactions are slow Lead dioxide is well known for being a good oxidizing agent, with an example reaction listed below: Although the formula of lead dioxide is nominally given as PbO, the actual oxygen to lead ratio varies between 1.90 and 1.98 depending

title: Carbon dioxide sensor

text: Carbon dioxide sensor A carbon dioxide sensor or CO sensor is an instrument for the measurement of carbon dioxide gas. The most common principles for CO sensors are infrared gas sensors (NDIR) and chemical gas sensors. Measuring carbon dioxide is important in monitoring indoor air quality, the function of the lungs in the form of a capnograph device, and many industrial processes. NDIR sensors are spectroscopic sensors to detect CO in a gaseous environment by its characteristic absorption. The key components are an infrared source, a light tube, an interference (wavelength) filter, and an infrared detector. The gas is pumped

title: Herbert Bowyer Berkeley

text: pre-coated, semi-dry collodion plates which were commercially available at that time. He discovered that with the addition of sulfite to Samman's developing solution, in order to absorb the sulphur dioxide, which was given off by the chemical dithionite, that dithionite was no longer required in the developing process. Berkeley published his discovery in 1881. In 1882 the "British Journal of Photography Almanac" included his new formula of pyrogallol, sulfite and citric acid in their publication. In Berkeley's new formula, just before use, ammonia was added to make it more alkaline. In London, Berkeley was a member of the Platinotype Company

title: Carbon dioxide sensor

text: measurement principle. Most CO₂ sensors are fully calibrated prior to shipping from the factory. Over time, the zero point of the sensor needs to be calibrated to maintain the long term stability of the sensor. Carbon dioxide sensor A carbon dioxide sensor or CO sensor is an instrument for the measurement of carbon dioxide gas. The most common principles for CO sensors are infrared gas sensors (NDIR) and chemical gas sensors. Measuring carbon dioxide is important in monitoring indoor air quality, the function of the lungs in the form of a capnograph device, and many industrial processes. NDIR sensors are

title: Titanium dioxide

text: deodorizing and anti-fouling properties and is used as a hydrolysis catalyst. It is also used in dye-sensitized solar cells, which are a type of chemical solar cell (also known as a Graetzel cell). The photocatalytic properties of titanium dioxide were discovered by Akira Fujishima in 1967 and published in 1972. The process on the surface of the titanium dioxide was called the Honda-Fujishima effect (). Titanium dioxide, in thin film and nanoparticle form has potential for use in energy production: as a photocatalyst, it can break water into hydrogen and oxygen. With the hydrogen collected, it could be used as

title: The Sulphur Institute

text: several available in Spanish, Chinese, and Hindi. The Sulphur Institute The Sulphur Institute, or TSI, is an international non-profit organization which acts as a global advocate for sulfur and sulfur producers. The Sulphur institute was founded in 1960, initially working with companies involved in the mining of sulfur using the Frasch process. With the increase of the Claus process for extracting sulfur from natural gas and oil, TSI's members now include multinational energy companies. The Sulphur Institute connects these sulfur producers with sulfur's largest consumer markets (fertilzers and construction materials), transporters, traders, and service providers. Today, The Sulphur Institute's member

title: The Sulphur Institute

text: The Sulphur Institute The Sulphur Institute, or TSI, is an international non-profit organization which acts as a global advocate for sulfur and sulfur producers. The Sulphur institute was founded in 1960, initially working with companies involved in the mining of sulfur using the Frasch process. With the increase of the Claus process for extracting sulfur from natural gas and oil, TSI's members now include multinational energy companies. The Sulphur Institute connects these sulfur producers with sulfur's largest consumer markets (fertilzers and construction materials), transporters, traders, and service providers. Today, The Sulphur Institute's member companies include a host of companies from

title: Port Sulphur, Louisiana

text: down operations, as the price of sulphur dropped too low because large amounts of sulphur recovered during petroleum refining and from Canadian natural gas exploration were dumped on the international sulphur market. With inexpensive recovered sulphur in large supply, the large scale and expensive Frasch Process sulphur mining and storage operations proved to be uneconomical and were discontinued. The Freeport-McMoRan Port Sulphur facility was closed and sold. Hurricane Katrina destroyed much of what was left of the sulphur facility in August 2005, with a few buildings remaining. With the closing of Freeport-McMoRan Sulphur, the town has been seeking another economic

title: Chemical composition

text: Chemical composition Chemical composition refers to the identity and relative number of the chemical elements that make up any particular compound. The chemical composition of a pure substance corresponds to the relative amounts of the elements that constitute the substance itself. It can be expressed with a chemical formula, such as an empirical or molecular formula. For example, the chemical formula for water is HO: this means that each molecule of water is constituted by 2 atoms of hydrogen (H) and 1 atom of oxygen (O). Thus the chemical composition of water may be interpreted as a 2:1 ratio of

title: Sulphur Channel

text: Possession Point (what is today Hollywood Road Park). After raising a toast to the Queen with his companions, he officially declared the island the property of Her Majesty Queen Victoria and a Colony of the British Empire. In 1990s, the Hong Kong Government had planned to reclaim the channel but withdrew later due to opposition from environmental concern groups. Sulphur Channel The Sulphur Channel is a narrow inshore passage between Green Island and the northwest tip of Hong Kong Island in Hong Kong. The Sulphur Channel is mainly used by small craft and inter-island ferries passing between Victoria Harbour and

title: Formula for primes

text: Formula for primes In number theory, a formula for primes is a formula generating the prime numbers, exactly and without exception. No such formula which is efficiently computable is known. A number of constraints are known, showing what such a "formula" can and cannot be. A simple formula is By Wilson's theorem, formula_3 is prime if and only if formula_4. Thus, when formula_3 is prime, the first factor in the product becomes one, and the formula produces the prime number formula_3. But when formula_3 is not prime, the first factor becomes zero and the formula produces the prime number 2.

title: Carbon dioxide

text: combustion of all carbon-based fuels, such as methane (natural gas), petroleum distillates (gasoline, diesel, kerosene, propane), coal, wood and generic organic matter produces carbon dioxide and, except in the case of pure carbon, water. As an example, the chemical reaction between methane and oxygen: It is produced by thermal decomposition of limestone, by heating (calcining) at about , in the manufacture of quicklime (calcium oxide, ), a compound that has many industrial uses: Iron is reduced from its oxides with coke in a blast furnace, producing pig iron and carbon dioxide: Carbon dioxide is a byproduct of the industrial production

title: Supercritical carbon dioxide

text: selectively dissolve organic compounds and assist the functioning of enzymes, s has been suggested as a potential solvent to support biological activity on Venus- or super-Earth-type planets. Environmentally beneficial, low-cost substitutes for rigid thermoplastic and fired ceramic are made using s as a chemical reagent. The s in these processes is reacted with the alkaline components of fully hardened hydraulic cement or gypsum plaster to form various carbonates. The primary byproduct is water. Supercritical carbon dioxide is used in the foaming of polymers. Supercritical carbon dioxide can saturate the polymer with solvent. Upon depressurization and heating the carbon dioxide rapidly

title: Nitrogen dioxide

text: the colorless dinitrogen tetroxide () below . The bond length between the nitrogen atom and the oxygen atom is 119.7 pm. This bond length is consistent with a bond order between one and two. Unlike ozone, O, the ground electronic state of nitrogen dioxide is a doublet state, since nitrogen has one unpaired electron, which decreases the alpha effect compared with nitrite and creates a weak bonding interaction with the oxygen lone pairs. The lone electron in also means that this compound is a free radical, so the formula for nitrogen dioxide is often written as . The reddish-brown color

title: Carbon dioxide reforming

text: Carbon dioxide reforming Carbon dioxide reformation (also known as dry reformation) is a method of producing synthesis gas (mixtures of hydrogen and carbon monoxide) from the reaction of carbon dioxide with hydrocarbons such as methane. Synthesis gas is conventionally produced via the steam reforming reaction. In recent years, increased concerns on the contribution of greenhouse gases to global warming have increased interest in the replacement of steam as reactant with carbon dioxide. The dry reforming reaction may be represented by: Thus, two greenhouse gases are consumed and useful chemical building blocks, hydrogen and carbon monoxide, are produced. A challenge to

title: Photochemical carbon dioxide reduction

text: Photochemical carbon dioxide reduction Photochemical carbon dioxide reduction harnesses solar energy to convert into higher-energy products. The chemical conversion of CO already occurs on an industrial scale in the manufacture of solvents such as formic acid, but photochemical reduction differs in that it relies on a renewable energy source, the sun. Because CO is a greenhouse gas, there is environmental interest in producing artificial systems that are efficient photocatalysts, but the low turn-over rates of current methods have prohibited wide-scale industrial application. Photochemical reduction follows from chemical reduction (redox). But, it differs in that the electrons used for reduction are

title: Xenon dioxide

text: Xenon dioxide Xenon dioxide, or xenon(IV) oxide, is a compound of xenon and oxygen with formula XeO, which was synthesized in 2011. It is synthesized at 0 °C by hydrolysis of xenon tetrafluoride (with 2.00 mol/L HSO). has an extended (chain or network) structure in which xenon and oxygen have coordination numbers of four and two respectively. The geometry at xenon is square planar, consistent with VSEPR theory for four ligands and two lone pairs (or AXE in the notation of VSEPR theory). In addition, the existence of an XeO molecule was predicted by an ab initio quantum chemistry method

title: Formula for primes

text: that there is a trivial program that enumerates all and only the prime numbers, as well as more efficient ones, so such recurrence relations are more a matter of curiosity than of any practical use. Formula for primes In number theory, a formula for primes is a formula generating the prime numbers, exactly and without exception. No such formula which is efficiently computable is known. A number of constraints are known, showing what such a "formula" can and cannot be. A simple formula is By Wilson's theorem, formula_3 is prime if and only if formula_4. Thus, when formula_3 is prime,

title: Structural formula

text: Structural formula The structural formula of a chemical compound is a graphic representation of the molecular structure, showing how the atoms are arranged. The chemical bonding within the molecule is also shown, either explicitly or implicitly. Unlike chemical formulas, which have a limited number of symbols and are capable of only limited descriptive power, structural formulas provide a complete geometric representation of the molecular structure. For example, many chemical compounds exist in different isomeric forms, which have different enantiomeric structures but the same chemical formula. A structural formula is able to indicate arrangements of atoms in three-dimensional space in a

title: Carbon dioxide

text: from the fact that, unlike water or other chemical based methods, Carbon dioxide will not cause short circuits, leading to even more damage to equipment. Because it is a gas, it is also easy to dispense large amounts of the gas automatically in IT infrastructure rooms, where the fire itself might be hard to reach with more immediate methods because it is behind rack doors and inside of cases. Carbon dioxide has also been widely used as an extinguishing agent in fixed fire protection systems for local application of specific hazards and total flooding of a protected space. International Maritime

title: Algebraic formula for the variance

text: for the "n" by "m" cross-covariance matrix "between" two random vectors of length "n" and "m": where expectations are taken element-wise and formula_8 and formula_9 are random vectors of respective lengths "n" and "m". Note that this formula suffers from the same loss of significance as the formula for variance if used for calculating estimates of the covariance, and alternative algorithms should be used instead. Algebraic formula for the variance In probability theory and statistics, there are several algebraic formulae for the variance available for deriving the variance of a random variable. The usefulness of these depends on what is

title: Miracle Mineral Supplement

text: speaking at seminars and selling chlorine dioxide or similar substances for the treatment of autism. However, Rivera operates a Facebook page and website that promote injecting autistic children with a toxic chlorine dioxide formula via enema, and claims that the intestinal lining and membranes children expel as a result are parasites, which is patently false. Then-Attorney General Lisa Madigan described the case by saying, "You have a situation where there are people, complete quacks, that are out there promoting a very dangerous chemical being given to young children... Ingesting what amounts to a toxic chemical - bleach - is not

title: Electrochemical reduction of carbon dioxide

text: Electrochemical reduction of carbon dioxide The electrochemical reduction of carbon dioxide (ERC) is the conversion of carbon dioxide to more reduced chemical species using electrical energy. The first examples of electrochemical reduction of carbon dioxide are from the 19th century, when carbon dioxide was reduced to carbon monoxide using a zinc cathode. Research in this field intensified in the 1980s following the oil embargoes of the 1970s. Electrochemical reduction of carbon dioxide represents a possible means of producing chemicals or fuels, converting carbon dioxide () to organic feedstocks such as formic acid (HCOOH), methanol (CHOH), ethylene (CH), methane (CH), and

title: Osmium dioxide

text: A typical transport agent is via the reversible formation of volatile OsO: OsO does not dissolve in water but is attacked by dilute hydrochloric acid. The crystals have rutile structure. Unlike osmium tetroxide, OsO is not toxic. Osmium dioxide Osmium dioxide is an inorganic compound with the formula OsO. It exists as brown to black crystalline powder, but single crystals are golden and exhibit metallic conductivity. The compound crystallizes in the rutile structural motif, i.e. the connectivity is very similar to that in the mineral rutile. OsO can be obtained by the reaction of osmium with a variety of oxidizing

title: Hafnium dioxide

text: passive cooling of buildings. The films reflect sunlight and radiate heat at wavelengths that pass through Earth's atmosphere, and can have temperatures several degrees cooler than surrounding materials under the same conditions. Hafnium dioxide Hafnium(IV) oxide is the inorganic compound with the formula HfO. Also known as hafnia, this colourless solid is one of the most common and stable compounds of hafnium. It is an electrical insulator with a band gap of 5.3~5.7 eV. Hafnium dioxide is an intermediate in some processes that give hafnium metal. Hafnium(IV) oxide is quite inert. It reacts with strong acids such as concentrated sulfuric

title: Hafnium dioxide

text: Hafnium dioxide Hafnium(IV) oxide is the inorganic compound with the formula HfO. Also known as hafnia, this colourless solid is one of the most common and stable compounds of hafnium. It is an electrical insulator with a band gap of 5.3~5.7 eV. Hafnium dioxide is an intermediate in some processes that give hafnium metal. Hafnium(IV) oxide is quite inert. It reacts with strong acids such as concentrated sulfuric acid and with strong bases. It dissolves slowly in hydrofluoric acid to give fluorohafnate anions. At elevated temperatures, it reacts with chlorine in the presence of graphite or carbon tetrachloride to give

title: Chemical chameleon

text: Chemical chameleon The chemical chameleon is a redox reaction, well known from classroom demonstrations, that exploits the dramatic color changes associated with the various oxidation states of manganese. Glauber reported the first description of the production of potassium permanganate when he noted that manganese dioxide (as the mineral pyrolusite) could be reacted at high temperatures with alkali to obtain a material that dissolved in water to give a green solution which slowly shifted to a violet-red. This process, similar to that still used in the production of potassium permanganate, oxidized manganese dioxide to potassium manganate which, acidified by carbon dioxide

title: The Sulphur Institute

text: addresses environmental and safety issues surrounding the transportation, production, and storage of sulfur. The Sulphur Institute's program allows regulatory agencies and industry stakeholders to connect, exchange knowledge, and develop practices which improve the safety of the industry. The Sulphur Institute provides members, government and non-government agencies, and industry stakeholders accurate information on sulfur. TSI has served as a source of industry information for many publications including the Wall Street Journal. TSI is often quoted by publications within the industry as well. The information gathered by TSI is made available through a number of publications, webinars, and speaking engagements. The Sulphur

title: Xenon dioxide

text: several years earlier by Pyykkö and Tamm, but these authors did not consider an extended structure. is a yellow-orange solid. It is an unstable compound, with a half-life of about two minutes, disproportionating into and xenon gas. Its structure and identity was confirmed by cooling it to −78 °C so that Raman spectroscopy could be performed before it decomposed. Xenon dioxide Xenon dioxide, or xenon(IV) oxide, is a compound of xenon and oxygen with formula XeO, which was synthesized in 2011. It is synthesized at 0 °C by hydrolysis of xenon tetrafluoride (with 2.00 mol/L HSO). has an extended (chain

title: Photochemical carbon dioxide reduction

text: and N-heterocyclic carbenes. Photochemical carbon dioxide reduction Photochemical carbon dioxide reduction harnesses solar energy to convert into higher-energy products. The chemical conversion of CO already occurs on an industrial scale in the manufacture of solvents such as formic acid, but photochemical reduction differs in that it relies on a renewable energy source, the sun. Because CO is a greenhouse gas, there is environmental interest in producing artificial systems that are efficient photocatalysts, but the low turn-over rates of current methods have prohibited wide-scale industrial application. Photochemical reduction follows from chemical reduction (redox). But, it differs in that the electrons used

title: Chlorine dioxide

text: be initiated by light, hot spots, chemical reaction, or pressure shock. Thus, chlorine dioxide gas is never handled in concentrated form, but is almost always handled as a dissolved gas in water in a concentration range of 0.5 to 10 grams per liter. Its solubility increases at lower temperatures, thus it is common to use chilled water (5 °C, or 41 °F) when storing at concentrations above 3 grams per liter. In many countries, such as the United States, chlorine dioxide gas may not be transported at any concentration and is almost always produced at the application site using a

title: Sulphur Bank Mine

text: the mercury into gas and recondense it to quicksilver. The sulfur would burn and convert to sulfur dioxide; the waste rock associated with the ore is known as calcine, or burnt rock, would be dumped near the lake shore, out of the way of the mining works. All of the furnaces at all of the mines in the vicinity were wood fired. The heyday of quicksilver mining came to an end when the price of quicksilver dropped to $25 per flask from a high in 1874 of $120. The Sulphur Bank Quicksilver Mining Company was bankrupt by 1883. Tiburcio Parrot’s

title: Supercritical carbon dioxide

text: the supercritical state and injected into geological storage, possibly into existing oil fields to improve yields. The unique properties of s ensure that it remains out of the atmosphere. Supercritical could be used as a working fluid in enhanced geothermal systems. Possible advantages compared to water include higher energy yield resulting from its lower viscosity, better chemical interaction, storage through fluid loss and higher temperature limit. As of 2011, the concept had not been tested in the field. Supercritical carbon dioxide is used in the production of silica, carbon and metal based aerogels. For example, silicon dioxide gel is formed

title: Sulphur Springs, Jefferson County, Arkansas

text: Sulphur Springs, Jefferson County, Arkansas Sulphur Springs, also known as White Sulphur Springs, is a census-designated place (CDP) in Spring Township, Jefferson County, Arkansas, United States. Its population was 1,101 as of the 2010 census. Until 1819, the area west of Pine Bluff through what is now Jefferson and Grant counties was a mostly unpopulated wilderness. In that year, the Mississippi and Arkansas rivers flooded the Delta area east of Pine Bluff, covering all of southeast Arkansas except for some of the absolute high points. This western area was very hilly, and had mostly small streams which did not flood.

title: Chemical compound

text: of atoms (chemical elements) in a fixed stoichiometric proportion can be termed a "chemical compound"; the concept is most readily understood when considering pure chemical substances. It follows from their being composed of fixed proportions of two or more types of atoms that chemical compounds can be converted, via chemical reaction, into compounds or substances each having fewer atoms. The ratio of each element in the compound is expressed in a ratio in its chemical formula. A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using the standard abbreviations

title: Formula

text: often algebraic, closed form, and/or analytical. In modern chemistry, a chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols, numbers, and sometimes other symbols, such as parentheses, brackets, and plus (+) and minus (−) signs. For example, HO is the chemical formula for water, specifying that each molecule consists of two hydrogen (H) atoms and one oxygen (O) atom. Similarly, O denotes an ozone molecule consisting of three oxygen atoms and having a net negative charge. In a general context, formulas are

title: Sulfur dioxide

text: a versatile inert solvent widely used for dissolving highly oxidizing salts. It is also used occasionally as a source of the sulfonyl group in organic synthesis. Treatment of aryl diazonium salts with sulfur dioxide and cuprous chloride yields the corresponding aryl sulfonyl chloride, for example: Injections of sulfur dioxide in the stratosphere has been proposed in climate engineering. The cooling effect would be similar to what has been observed after the large explosive volcano eruption of Mount Pinatubo in 1991. However this form of geoengineering would have uncertain regional consequences on rainfall patterns, for example in monsoon regions. Sulfur dioxide

title: Chemical laser

text: Chemical laser A chemical laser is a laser that obtains its energy from a chemical reaction. Chemical lasers can reach continuous wave output with power reaching to megawatt levels. They are used in industry for cutting and drilling. Common examples of chemical lasers are the chemical oxygen iodine laser (COIL), all gas-phase iodine laser (AGIL), and the hydrogen fluoride (HF) and deuterium fluoride (DF) lasers, all operating in the mid-infrared region. There is also a DF–CO laser (deuterium fluoride–carbon dioxide), which, like COIL, is a "transfer laser." The HF and DF lasers are unusual, in that there are several molecular

title: Chemical formula

text: number of repeating units is unknown or variable, the letter "n" may be used to indicate this formula: CH(CH)CH. For ions, the charge on a particular atom may be denoted with a right-hand superscript. For example, Na, or Cu. The total charge on a charged molecule or a polyatomic ion may also be shown in this way. For example: HO or SO. Note that + and - are used in place of +1 and -1, respectively. For more complex ions, brackets [ ] are often used to enclose the ionic formula, as in [BH], which is found in compounds such

title: The Sulphur Institute

text: working with representatives in India to encourage similar growth in sulfur usage. TSI worked with the International Fertilizer Industry Association and the Fertilizer Association of India to provide activities and resources on the use of sulfur in agriculture. TSI serves as a spokesperson for the sulfur industry with its Transportation Regulations and Logistics program. "TSI monitors for proposed changes to regulations impacting transportation and handling of sulfur and sulfur compounds." Their program covers transportation by rail, road, and sea transportation on regional, national, and international levels. The Sulphur Institute holds an international symposium annually titled The Sulphur Institute's Sulphur World

title: Silicon dioxide

text: between 600 and 1200 °C, using so-called dry or wet oxidation with O or HO, respectively. The native oxide layer is beneficial in microelectronics, where it acts as electric insulator with high chemical stability. It can protect the silicon, store charge, block current, and even act as a controlled pathway to limit current flow. Many routes to silicon dioxide start with silicate esters, the best known being tetraethyl orthosilicate (TEOS). Simply heating TEOS at 680–730 °C gives the dioxide: Similarly TEOS combusts around 400 °C: TEOS undergoes hydrolysis via the so-called sol-gel process. The course of the reaction and nature

title: Structural formula

text: same chemical compound. Another example is formal double bonds where the electron density is spread outside the formal bond, leading to partial double bond character and slow inter-conversion at room temperature. For all dynamic effects, temperature will affect the inter-conversion rates and may change how the structure should be represented. There is no explicit temperature associated with a structural formula, although many assume that it would be standard temperature. Structural formula The structural formula of a chemical compound is a graphic representation of the molecular structure, showing how the atoms are arranged. The chemical bonding within the molecule is also

title: Sulphur Springs, Saint Lucia

text: into a pit and received second degree burns from just above his waist, the formation of what is now known as Gabriel's Hole has restricted viewing to a platform a few hundred feet away. A couple of hundred yards downstream from the springs, the water temperature is still hot (around 110 Fahrenheit or 45 Celsius), but cool enough for tourists to enter and give themselves a mud bath. These mud baths are believed by some to have medicinal properties and are used by some tourists and locals for said reasons. http://www.saintluciavolcanotour.com/ Sulphur Springs, Saint Lucia Sulphur Springs is the "world's

title: Sulphur Springs Cemetery (Sulphur Springs, Arkansas)

text: spa community of Sulphur Springs, which flourished here in the 19th century. The cemetery was listed on the National Register of Historic Places in 2012. Sulphur Springs Cemetery (Sulphur Springs, Arkansas) Sulphur Springs Cemetery is a historic cemetery in rural northern Yell County, Arkansas. It is located northwest of Chickalah, on the south side of County Road 39 (Slo Fork Road), about west of its junction with County Road 38. The cemetery contains 26 marked burial sites on just over of the property, dating from 1844 to 1940. There are at least two known unmarked burials, and fieldstones in the