At standard temperature and pressure, oxygen exists as a diatomic molecule with the formula O2, in which the two oxygen atoms are doubly bonded to each other. In its most stable form, oxygen exists as a diradical (triplet oxygen). Though radicals are commonly associated with highly reactive compounds, triplet oxygen is surprisingly (and fortunately) unreactive towards most compounds. Singlet oxygen, a name given to several higher energy species in which all the electron spins are paired, is much more ...

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Oxygen, Oxygen - Characteristics, Oxygen - Applications, Oxygen - History, Oxygen - Occurrence, Oxygen - Compounds, Oxygen - Isotopes, Oxygen - Precautions

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Oxygen, Oxygen - Characteristics, Oxygen - Applications, Oxygen - History, Oxygen - Occurrence, Oxygen - Compounds, Oxygen - Isotopes, Oxygen - Precautions

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Liquid oxygen finds use as an oxidizer in rocket propulsion. Oxygen is essential to respiration, so oxygen supplementation has found use in medicine (as oxygen therapy). People who climb mountains or fly in airplanes sometimes have supplemental oxygen supplies (as air). Oxygen is used in welding (such as the oxyacetylene torch), and in the making of steel and methanol. Oxygen presents two absorption bands centered in the wavelengths 687 and 760 nanometers. Some scientists have proposed to use the measurement of the radiance coming fro ...

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Oxygen, Oxygen - Characteristics, Oxygen - Applications, Oxygen - History, Oxygen - Occurrence, Oxygen - Compounds, Oxygen - Isotopes, Oxygen - Precautions

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Oxygen is a chemical element in the periodic table. It has the symbol O and atomic number 8. The element is very common, found not only on Earth but throughout the universe, usually covalently bonded with other elements. Unbound oxygen (usually called molecular oxygen, O2, a diatomic molecule) first appeared on Earth during the Paleoproterozoic era (between 2500 million years ago and 1600 million years ago) and as a product of the metabolic action of early anaerobes (archaea and bacteria). The presence of free oxygen ...

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Oxygen - Characteristics Oxygen - Applications Oxygen - History Oxygen - Occurrence Oxygen - Compounds Oxygen - Isotopes Oxygen - Precautions

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Organic reaction - Nitrogen containing compounds. Pinner reaction Organic reaction - Phosphorus containing compounds. Reactions, by reactants: aromatic compounds. ...

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Organic reaction, Organic reaction - Reactions by reactants: aliphatic compounds, Organic reaction - Alkanes RH, Organic reaction - Alkenes R1R2C=CR3R4 and Alkynes R1C≡CR2, Organic reaction - Hydrocarbons plus Group 17 Halogen, Organic reaction - Alkyl halides RX, Organic reaction - Hydrocarbons plus Group 16 Chalcogen, Organic reaction - Oxygen containing compounds, Organic reaction - Sulfur containing compounds, Organic reaction - Hydrocarbons plus Group 15 Pnictogen, Organic reaction - Nitrogen containing compounds, Organic reaction - Phosphorus containing compounds, Organic reaction - Benzene and derivatives, Organic reaction - Other reactions unsorted

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Organic reaction - Oxygen containing compounds. Primary alcohols = SN2 Tertiary alcohols = SN1 Secondary alcohols = SN1 or SN2 (SNX) Also see Baeyer-Villiger oxidation Organic reaction - Sulfur containing compounds. ...

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Organic reaction, Organic reaction - Reactions by reactants: aliphatic compounds, Organic reaction - Alkanes RH, Organic reaction - Alkenes R1R2C=CR3R4 and Alkynes R1C≡CR2, Organic reaction - Hydrocarbons plus Group 17 Halogen, Organic reaction - Alkyl halides RX, Organic reaction - Hydrocarbons plus Group 16 Chalcogen, Organic reaction - Oxygen containing compounds, Organic reaction - Sulfur containing compounds, Organic reaction - Hydrocarbons plus Group 15 Pnictogen, Organic reaction - Nitrogen containing compounds, Organic reaction - Phosphorus containing compounds, Organic reaction - Benzene and derivatives, Organic reaction - Other reactions unsorted

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In environmental chemistry, the chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in water. Most applications of COD determine the amount of organic pollutants found in surface water (e.g. lakes and rivers), making COD a useful measure of water quality. It is expressed in millgrams per liter (mg/L), which indicates the mass of oxygen consumed per liter of solution. Older references may express the units as parts per million (ppm). Chemical oxygen demand - Over ...

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Chemical oxygen demand - Overview Chemical oxygen demand - History Chemical oxygen demand - Using potassium dichromate
Chemical oxygen demand - Blanks Chemical oxygen demand - Measurement of excess Chemical oxygen demand - Calculations
Chemical oxygen demand - Inorganic interference Chemical oxygen demand - Government regulation

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In chemistry, aliphatic compounds are non-aromatic and non-cyclic organic compounds. They include not only the fatty acids and other derivatives of the paraffin hydrocarbons, but also unsaturated compounds, such as the ethylene (alkene) and acetylene (alkyne) series. Aliphatic molecules consist, generally, of a backbone of carbon atoms and other atoms bound to this carbon chain — most frequently hydrogen, oxygen, nitrogen, sulfur, and various halides. The ...

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The chalcogens (with the "ch" pronounced with a hard "c" as in "chemistry") are the name for the periodic table group 16 (old-style: VIB or VIA) in the periodic table. It is sometimes known as the oxygen family. It consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), the radioactive polonium (Po), and the synthetic ununhexium (Uuh). The compounds of the heavier chalcogens (particularly the sulfides, selenides, and tellurides) are collectively known as chalcogenides. Unless grouped with a heavier cha ...

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Chemical decomposition or analysis is the fragmentation of a chemical compound into elements or smaller compounds. It is sometimes defined as the opposite of a synthesis. A generalized reaction formula is: AB → A + B. An example of analysis is the electrolysis of water 2H2O → 2H2 + O2. Another recognized form of decomposition is hydrogen peroxide. If you keep it for a long time, the hydrogen peroxide will eventually decompose into water and oxygen: 2H ...

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A chemical compound is a chemical substance formed from two or more elements, with a fixed ratio determining the composition. For example, dihydrogen monoxide (water, H2O) is a compound composed of two hydrogen atoms for every oxygen atom. In general, this fixed ratio must be fixed due to some sort of physical property, rather than an arbitrary man-made selection. This is why materials such as brass, the superconductor YBCO, the semiconductor aluminium gallium arsenide, or chocolate ...

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Chemical compound - Types of compounds

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In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom. The term carbonyl can also refer to carbon monoxide as a ligand in an inorganic or organometallic complex (e.g., nickel carbonyl); in this situation, carbon is triple-bonded to oxygen. A carbonyl group characterizes the following types of compounds (where -CO denotes a C=O carbonyl group): aldehyde- (R-CHO) ketone- (R-CO-R1) carboxylic acid- (R-COOH) ester- (R ...

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Carbonyl - Reactivity Carbonyl - αβ-unsaturated carbonyl compounds Carbonyl - Spectroscopy

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Environmental Pollution is the release of harmful environmental contaminants, or the substances so released. Generally the process needs to result from human activity to be regarded as pollution. Even relatively benign products of human activity are liable to be regarded as pollution, if they precipitate negative effects later on. The nitrogen oxides produced by industry are often referred to as pollution, for example, although the substances themselves are not harmful. In fact, it is solar energy ( ...

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Pollution - Headline text Pollution - Regulation and Monitoring
Pollution - International Pollution - United States

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Ether is the general name for a class of chemical compounds which contain an ether group — an oxygen atom connected to two (substituted) alkyl groups. A typical example is the solvent and anesthetic diethyl ether (ethoxyethane, CH3-CH2-O-CH2-CH3). Ether - Similar structures. Ethers are not to be confused with the following classes of compounds with the same general structure R-O-R. Aromatic compounds like furan where the oxygen is part of the aromat ...

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Ether - Similar structures Ether - Primary secondary and tertiary ethers Ether - Polyethers Ether - Chemical reactions
Ether - Synthesis Ether - Reactions
Ether - Physical properties Ether - Nomenclature Ether - Important ethers

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Azadirachtin A is a chemical compound belonging to the limonoids. It is a secondary metabolite present in the Neem tree seeds. The molecular formula is C35H44O16. Azadirachtin A is a highly oxidised tetranortriterpenoid which boasts a plethora of oxygen functionality, comprising an enol ether, acetal, hemiacetal, and tetra-substituted oxirane as well as a variety of carboxylic esters. It is classified among the plant secondary metabolites.

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In chemistry, to bleach something generally means to whiten it or oxidize it. A bleach is a chemical that can produce these effects. Common chemical bleaches include sodium hypochlorite, or "chlorine bleach," and "oxygen bleach," which contains hydrogen peroxide or a peroxide-releasing compound (eg. sodium perborate, or sodium percarbonate). "Bleaching powder" is calcium hypochlorite. Bleaching can be ...

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Bleach - History Bleach - Hazards

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The Born-Haber cycle is a famous cycle of chemical reactions, first developed by Max Born and the German chemist Fritz Haber in 1917. The Born-Haber cycle involves the formation of an ionic compound from the reaction of a metal (often a group I or group 2 element) with a non-metal (like gaseous halogens, oxygen, sulfur or others). Born-Haber cycles are used primarily as a means of calculating lattice e ...

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Rust is the substance formed when iron compounds corrode in the presence of oxygen and water. It is a mixture of iron oxides and hydroxides. Rusting is a common term for corrosion, and usually corrosion of steel. Iron is found naturally in the ore hematite as iron oxide, and metallic iron tends to return to a similar state when exposed to air, (hydrogen, oxygen, nitrogen, etc) and water. This corrosion is due to the oxidation reaction when iron metal returns to an energetically favourable state. Energy is given off when rust fo ...

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Aluminium oxide or aluminum oxide is a chemical compound of aluminium and oxygen with the chemical formula Al2O3. It is also commonly referred to as alumina in the mining, ceramic, and materials science communities. Alumina is generally available in two concentrations: 99.5% and 96%. Aluminium oxide is responsible for metallic aluminium's resistance to weathering. Metallic aluminium is very reactive with atmospheric oxygen, and a thin passivation layer of aluminium oxide quickly forms on any ...

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Aluminium oxide - Industrial Fabrication Process

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Chromium is a chemical element in the periodic table that has the symbol Cr and atomic number 24. Chromium - Notable characteristics. Chromium is a steel-gray, lustrous, hard metal that takes a high polish, melts with difficulty, and tarnishes. The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +4 and +5 are rare. Chromium compounds of oxidation state 6 are powerful oxidants. Chromium(0) is unstable in oxygen, immediately producing a thin oxi ...

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Chromium - Notable characteristics Chromium - Applications Chromium - History Chromium - Biological role Chromium - Occurrence Chromium - Compounds Chromium - Isotopes Chromium - Chromium and the quintuple bond Chromium - Precautions

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