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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Colloidal gold is a suspension (or colloid) of sub-micrometre-sized particles in a fluid, usually water. The liquid is usually either an intense red colour (for particles less than 100 nm), or a dirty yellowish colour (for larger particles) [1] [2]. Known since ancient times, it was originally used as a method of staining glass; however, serious research into colloid ...

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Colloidal gold - Synthesis
Colloidal gold - Turkevitch et al. method Colloidal gold - Brust et al. method
Colloidal gold - History Colloidal gold - Current research

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Chloroprene is the common name for the organic compound 2-chloro-1,3-butadiene, which has the chemical formula C4H5Cl. The chemical structure is shown at right. It is used as monomer for the production of the polymer polychloroprene, a type of synthetic rubber. Polychloroprene is better known to the public as Neoprene, the trade name DuPont gave it when the company fi ...

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Chloroprene - Production of chloroprene

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Silver is a chemical element with the symbol Ag (from the traditional abbreviation for the Latin argentum). A soft white lustrous transition metal, it has the highest electrical and thermal conductivity of any metal and occurs in minerals and in free form. This metal is used in coins, jewelry, tableware, and photography. Silver - Notable characteristics. Silver is a very ductile and malleable (slightly harder than gold) univalent coinage metal with a brilliant white metallic luster that can ta ...

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Silver - Notable characteristics Silver - Applications Silver - History Silver - Occurrence Silver - Isotopes Silver - Precautions and health effects

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Gold is a chemical element in the periodic table that has the symbol Au (L. aurum) and atomic number 79. A soft, shiny, yellow, dense, malleable, ductile (trivalent and univalent) transition metal, gold does not react with most chemicals but is attacked by chlorine, fluorine and aqua regia. The metal occurs as nuggets or grains in rocks and in alluvial deposits and is one of the coinage metals. For millennia, gold has served as money and is also used in jewellery, dentistry, and in electronics. Gold forms t ...

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Gold - Notable characteristics Gold - Applications Gold - History Gold - Value Gold - Gold and the money supply Gold - Restrictions on gold ownership Gold - Return of a gold standard? Gold - Gold in investment portfolios Gold - Occurrence Gold - Production Gold - Compounds/isotopes Gold - Precautions Gold - Symbolism

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Carboxylic acids are widespread in nature. Carboxylic acids are typically weak acids that partially dissociate into H+ cations and RCOO- anions in aqueous solution. For example, only about 0.02% of all acetic acid molecules are dissociated at room temperature in solution. The two electronegative oxygen atoms tend to pull the electron away from the hydrogen of the hydroxyl group, and the remaining proton H+ can more easily leave. The remaining negative charge is then distributed symmetrically among the two oxygen atoms, and the two carbon–oxy ...

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Carboxylic acid, Carboxylic acid - Acidity electron distribution and resonance, Carboxylic acid - Synthesis, Carboxylic acid - Reactions, Carboxylic acid - Nomenclature and examples

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Silvery in appearance, neptunium metal is fairly chemically reactive and is found in at least three structural modifications: alpha-neptunium, orthorhombic, density 20.25 Mg/m3, beta-neptunium (above 280 °C), tetragonal, density (313 °C) 19.36 Mg/m3, and gamma-neptunium (above 577 °C), cubic, density (600 °C) 18 Mg/m3. This element has four ionic oxidation states while in solution: Np+3 (pale purple), analogous to the rare earth ion PmSee also:

Neptunium, Neptunium - Notable characteristics, Neptunium - History, Neptunium - Occurrence, Neptunium - Isotopes, Neptunium - Weapons applications

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Oxides can be named after the amount of oxygen atoms in the oxide. Oxides containing only one oxygen are called oxide or monoxide, those containing two oxygen atoms dioxide, three trioxide, four tetroxide, and so on following the Greek numerical prefixes. There are two other types of oxide—peroxide and superoxide. Both count as oxides but have different oxidation states and react in different ways compared to oxides. ...

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Oxide, Oxide - Current naming, Oxide - Chemical properties, Oxide - Types of oxides, Oxide - Common oxides sorted by oxidation state

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Palladium is a soft steel-white metal that resembles platinum, doesn't tarnish in air, and is the least dense and has the lowest melting point of the platinum group metals. It is soft and ductile when annealed and greatly increases its strength and hardness when it is cold-worked. Palladium is chemically attacked by sulfuric and nitric acid but dissolves slowly in hydrochloric acid. This metal al ...

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Palladium, Palladium - Notable characteristics, Palladium - Applications, Palladium - History, Palladium - Occurrence, Palladium - Isotopes

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The industrial extraction of rhodium is complex as the metal occurs in ores mixed with other metals such as palladium, silver, platinum, and gold. It is found in platinum ores and obtained free as a white inert metal which it is very difficult to fuse. Principal sources of this element are located in South Africa, in river sands of the Ural Mountains, in North and South America and also in the copper-nickel sulfide mining area of the Sudbury, Ontario region. Although the quantity at Sudbury is very small, the large amount of nickel ore proce ...

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Rhodium, Rhodium - Notable characteristics, Rhodium - Applications, Rhodium - History, Rhodium - Occurrence, Rhodium - Isotopes, Rhodium - Precautions

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After a failed attempt on the Eastern front, it was first used effectively in World War I by the German army against Canadian soldiers in 1917 and later also against the French – the name Yperite comes from its usage by the German army near the city of Ypres. It took the British over a year to develop their own mustard gas weapon, first using it in September 1918 during the breaking of the Hindenburg Line. Mustard gas was dispersed as an aerosol in a mixture with other chemicals, giving it a yellow-brown colour and a distinct ...

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Sulfur mustard, Sulfur mustard - Chemistry, Sulfur mustard - Physiological effects, Sulfur mustard - History, Sulfur mustard - Disposal of Mustard Gas

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12-Dichloroethane - Vinyl chloride monomer VCM production. With approximately 80% of the world's consumption of 1,2-dichloroethane, the major application is in the production of vinyl chloride monomer (VCM, chloroethen), which is the precursor to polyvinyl chloride under the formation of hydrogen chloride. Cl-CH2-CH2-Cl → H2C=CH-Cl + HCl The hydrogen chloride can be re-used in the production process, in the formation of more 1,2-dichloroethane (see Production). ...

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12-Dichloroethane, 12-Dichloroethane - History, 12-Dichloroethane - Chemistry, 12-Dichloroethane - Production, 12-Dichloroethane - Uses, 12-Dichloroethane - Vinyl chloride monomer VCM production, 12-Dichloroethane - Other uses, 12-Dichloroethane - Safety

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Mass spectrometry - Ion source. The ion source is the part of the mass spectrometer that ionizes the material under analysis (the analyte). The ions are then transported by magnetic or electrical fields to the mass analyzer. Techniques for ionization have been key to determining what types of samples can be analyzed by mass spectrometry. Electron ionization and chemical ionization are used for gases and vapors. In chemical ionization sources, the analyte is ionized by chemical ion-molecule reactions during ...

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Mass spectrometry, Mass spectrometry - How it works in layman terms, Mass spectrometry - Instrumentation, Mass spectrometry - Ion source, Mass spectrometry - Mass analyzer, Mass spectrometry - Detector, Mass spectrometry - Hyphenated MS, Mass spectrometry - Gas chromatography/MS, Mass spectrometry - Liquid chromatography/MS, Mass spectrometry - IMS/MS, Mass spectrometry - Tandem MS MS/MS, Mass spectrometry - Applications, Mass spectrometry - Isotope ratio MS, Mass spectrometry - Trace Gas Analysis, Mass spectrometry - Pharmcokinetics, Mass spectrometry - Mass spectrometry of proteins, Mass spectrometry - Protein and peptide fractionation coupled with mass spectrometry, Mass spectrometry - Protein identification, Mass spectrometry - History

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The 917 has two trays for racks, plus a stat rack. Racks that hold five test tubes slide in on the left side of the machine. There are two reagents carousels on the right side of the 917. In the centre, towards the back, are the reaction vessels, where the chemical reactions take place. Ion selective electrode (ISE) reagents and components are in front of the reaction carousel. ...

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Hitachi 917, Hitachi 917 - Appearance and use, Hitachi 917 - Tests available

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Hydrochloric acid was first discovered around the year 800 by Arab-Yemeni alchemist Jabir ibn Hayyan (Geber), by mixing common salt with vitriol (sulfuric acid). Jabir discovered or invented many important chemicals, and wrote his findings in over 20 books, which carried his chemical knowledge of hydrochloric acid and other basic chemicals for hundreds of years. Jabir's invention of the gold-dissolving aqua regia, consisting of hydrochloric acid and nitric acid, contributed to the effort of alche ...

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Hydrochloric acid, Hydrochloric acid - History, Hydrochloric acid - Chemistry, Hydrochloric acid - Production, Hydrochloric acid - Direct synthesis, Hydrochloric acid - Organic synthesis, Hydrochloric acid - Industrial market, Hydrochloric acid - Applications, Hydrochloric acid - Regeneration of ion exchangers, Hydrochloric acid - pH control and neutralization, Hydrochloric acid - Pickling of steel, Hydrochloric acid - Production of inorganic compounds, Hydrochloric acid - Production of organic compounds, Hydrochloric acid - Other applications, Hydrochloric acid - Hydrochloric acid and living organisms, Hydrochloric acid - Physiology, Hydrochloric acid - Pathophysiology and pathology, Hydrochloric acid - Chemical weapons, Hydrochloric acid - Safety

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Magnesium compounds, primarily magnesium oxide, are used mainly as refractory material in furnace linings for producing iron and steel, nonferrous metals, glass, and cement. Magnesium oxide and other compounds also are used in agricultural, chemical, and construction industries. As a metal, this element's principal use is as an alloying additive to aluminium with these aluminium-magnesium alloys being used mainly for beverage cans. Magnesium, in its purest form,is like aluminum, and is strong and light, so it is used in several high v ...

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Magnesium, Magnesium - Notable characteristics, Magnesium - Applications, Magnesium - History, Magnesium - Sources, Magnesium - Compounds in living organisms, Magnesium - Food sources, Magnesium - Isotopes, Magnesium - Precautions

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Perchlorates are a neurotoxin. They have been found to affect the thyroid gland in particular. When perchlorates enter the body, they block iodine uptake to the thyroid gland, which is needed to create thyroid hormones used by the body for metabolism as well as for growth and development in children. This can result in tumor growth on the thyroid gland. The chemical is particularly dangerous to women of childbearing age and developing fetuses, since it is known to cause mental retardation in unborn children as well as infants. Children up to ...

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Perchlorate, Perchlorate - Scientific definition, Perchlorate - Perchlorate pollution, Perchlorate - Types of perchlorates

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Salt's preservative ability was a foundation of civilization. It eliminated dependency on the seasonal availability of food and allowed travel over long distances. By the Middle Ages, caravans consisting of as many as forty thousand camels traversed four hundred miles of the Sahara bearing salt, sometimes trading it for slaves. Until the 1900s, salt was one of the prime movers of national economies and wars. Salt has played a prominent role in determining the power and location of the world's great cities. Timbuktu was once a huge sal ...

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Sodium chloride, Sodium chloride - Crystal structure, Sodium chloride - Biological importance, Sodium chloride - Salt throughout history, Sodium chloride - In religion, Sodium chloride - Production and use, Sodium chloride - Flavor enhancer, Sodium chloride - Biological uses, Sodium chloride - De-icing, Sodium chloride - Additives, Sodium chloride - Other facts

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The heaviest of the alkaline earth metals, radium is intensely radioactive and resembles Barium chemically. This metal is found (combined) in minute quantities in the uranium ore pitchblende, and various other uranium minerals. Radium preparations are remarkable for maintaining themselves at a higher temperature than their surroundings, and for their radiations, which are of three kinds: alpha rays, beta rays, and gamma rays. Radium ...

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Radium, Radium - Notable characteristics, Radium - Applications, Radium - History, Radium - Occurrence, Radium - Compounds, Radium - Isotopes, Radium - Radioactivity, Radium - Precautions

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Vanadium is a soft and ductile, gray-white metal. It has good resistance to corrosion by alkalis, sulfuric and hydrochloric acid. It oxidizes readily at about 933 K. Vanadium has good structural strength and a low fission neutron cross section, making it useful in nuclear applications. Although definitely a metal, it shares with Chromium and Manganese the property of having valency oxides with acid properties. Common oxidation states of vanadium include +2, +3, +4 and +5. A popular experiment with ammonium vanadate (NH4VOSee also:

Vanadium, Vanadium - Notable characteristics, Vanadium - Applications, Vanadium - History, Vanadium - Biological role, Vanadium - Occurrence, Vanadium - Isolation, Vanadium - Compounds, Vanadium - Isotopes, Vanadium - Precautions

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Like the other alkali metals, sodium metal is a soft, light-weight, silvery white, reactive metal. Owing to its extreme reactivity, in nature it occurs only combined into compounds, and never as a pure elemental metal. Sodium metal floats on water, and reacts violently with it releasing heat, flammable hydrogen gas and caustic sodium hydroxide solution. Sodium ions are necessary for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions. It is widely considered that most pe ...

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Sodium, Sodium - Notable characteristics, Sodium - Applications, Sodium - History, Sodium - Occurrence, Sodium - Compounds, Sodium - Isotopes, Sodium - Precautions, Sodium - Physiology and sodium ions

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