"Heavy water Heavy water (deuterium oxide, ', ') is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium ( or D, also known as ""heavy hydrogen""), rather than the common hydrogen-1 isotope ( or H, also called protium) that makes up most of the hydrogen in normal water. The presence of deuterium gives the chemical different nuclear properties, and the increase of mass gives it different physical and chemical properties compared to normal ""light water"". Deuterium is a hydrogen isotope with a nucleus containing a neutron and a proton; the nucleus of a"
"HMX HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the compound's name is the subject of much speculation, having been variously listed as High Melting Explosive, Her Majesty's Explosive, High-velocity Military Explosive, or High-Molecular-weight RDX. The molecular structure of HMX consists of an eight-membered ring of alternating carbon and nitrogen atoms, with a nitro group attached to each nitrogen atom. Because of its high molecular weight, it is one of the most potent chemical explosives manufactured, although a number of newer ones, including HNIW and ONC, are more powerful."
"binary compounds with hydrogen known as the hydrogen halides: hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen bromide (HBr), hydrogen iodide (HI), and hydrogen astatide (HAt). All of these compounds form acids when mixed with water. Hydrogen fluoride is the only hydrogen halide that forms hydrogen bonds. Hydrochloric acid, hydrobromic acid, hydroiodic acid, and hydroastatic acid are all strong acids, but hydrofluoric acid is a weak acid. All of the hydrogen halides are irritants. Hydrogen fluoride and hydrogen chloride are highly acidic. Hydrogen fluoride is used as an industrial chemical, and is highly toxic, causing pulmonary edema and damaging cells. Hydrogen"
"Polyhydride A polyhydride or superhydride is a compound that contains an abnormally large amount of hydrogen. This can be described as high hydrogen stoichiometry. Examples include iron pentahydride FeH, LiH, and LiH. The more well known lithium hydride only has one hydrogen atom. Polyhydrides are only known to be stable under high pressure. Polyhydrides are important because they can form substances with a very high density of hydrogen. They may resemble the elusive metallic hydrogen, but can be made under lower pressures. One possibility is that they could be superconductors. Hydrogen sulfide under high pressures forms SH units, and can"
"Heavy liquid A heavy liquid is a solution or liquid chemical substance with a high density and a relatively low viscosity. Heavy liquids are often used for determination of density in mineralogy, for density gradient centrifugation and for separating mixtures. Common applications of heavy liquids include: The classical heavy liquids like 1,1,2,2-tetrabromoethane (""Muthmanns solution""), potassium tetraiodomercurate(II) (""Thoulets solution""), bromoform or diiodomethane which are used in mineralogy are very toxic. These toxic chemicals are avoided today in consideration of the fact that there are alternative water based, non-toxic heavy liquids like sodium polytungstate solutions. With this relatively new heavy liquid densities"
"GPa). HSe actually is a van der Waals solid with formula 2HSe•H with a measured T of 105K under a pressure of 135 GPa. Polyhydride A polyhydride or superhydride is a compound that contains an abnormally large amount of hydrogen. This can be described as high hydrogen stoichiometry. Examples include iron pentahydride FeH, LiH, and LiH. The more well known lithium hydride only has one hydrogen atom. Polyhydrides are only known to be stable under high pressure. Polyhydrides are important because they can form substances with a very high density of hydrogen. They may resemble the elusive metallic hydrogen, but"
"produced by the P-9 Project: Chicago Pile 3 at Argonne, and ZEEP and NRX at the Chalk River Laboratories in Canada. Heavy water is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium, also known as heavy hydrogen, rather than the common hydrogen-1 isotope that makes up most of the hydrogen in ordinary water. Deuterium was discovered by Harold Urey in 1931 and he was later able to concentrate it in water. His mentor Gilbert Newton Lewis isolated the first sample of pure heavy water by electrolysis in 1933. Although a scientific curiosity"
"later named: in Greek, hydrogen means ""water-former"". Industrial production is mainly from steam reforming natural gas, and less often from more energy-intensive methods such as the electrolysis of water. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market. Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks. Hydrogen gas (dihydrogen or molecular hydrogen, also called diprotium when consisting specifically of a pair of protium atoms) is highly flammable and will"
"hydrogen, are heavy, black, sticky and either slow-pouring or so close to being solid that they will not pour at all unless heated. Although the dividing line is fuzzy, the term heavy oil refers to slow-pouring heavy hydrocarbon mixtures. Bitumen refers to mixtures with the consistency of cold molasses that pour at room temperatures with agonizing slowness. Oils with high viscosity and heavy gravity do not float on water, but sink. In the oil sands, this thick, black gunk is mixed with sand and many chemical impurities such as sulfur; these must be separated from the bitumen for the oil"
"called hydrogen bonding that is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as metals and metalloids, where it takes on a partial negative charge. These compounds are often known as hydrides. Hydrogen forms a vast array of compounds with carbon called the hydrocarbons, and an even vaster array with heteroatoms that, because of their general association with living things, are called organic compounds. The study of their properties is known as organic chemistry and their study in the context of living organisms is known as biochemistry. By some definitions, ""organic"""
"produced displayed a higher density than regular water. Heavy water has a higher freezing point, higher boiling point, and lower refractive index than regular water. Heavy water differs from regular water in that the two atoms of hydrogen have been substituted with two atoms of deuterium, which is an isotope of hydrogen. The mass of heavy water is about 10% more than that of regular water due to the extra neutron in deuterium. Heavy water was discovered by Gilbert N. Lewis in 1933. In 1934, Frandsen, along with Washburn and Smith, also published ""On Change in Density, Index of Refraction,"
"with the term ""heavy element"". For example, in discussing the history of nuclear chemistry, Magee notes that the actinides were once thought to represent a new heavy element transition group whereas Seaborg and co-workers ""favoured ... a heavy metal rare-earth like series ..."". In astronomy, however, a heavy element is any element heavier than hydrogen and helium. In 2002, Scottish toxicologist John Duffus reviewed the definitions used over the previous 60 years and concluded they were so diverse as to effectively render the term meaningless. Along with this finding, the heavy metal status of some metals is occasionally challenged on"
"has the formal oxidation state −1. The term hydride is probably most often used to describe compounds of hydrogen with other elements in which the hydrogen is in the formal −1 oxidation state. In most such compounds the bonding between the hydrogen and its nearest neighbor is covalent. An example of a hydride is the borohydride anion (). Hydrogen anion The hydrogen anion, H, is a negative ion of hydrogen, that is, a hydrogen atom that has captured an extra electron. The hydrogen anion is an important constituent of the atmosphere of stars, such as the Sun. In chemistry, this"
"and hydroperoxyl (HO) being the two simplest. The compound hydrogen ozonide (HO) is not known, although some of its alkali metal ozonide salts are; these having the formula MO. The respective sulfur analogue for hydroxyl is sulfanyl (HS). One or both of the protium atoms in water can be substituted with the isotope deuterium, yielding respectively semiheavy water and heavy water, the latter being one of the most famous deuterium compounds. Due to the high difference in density between deuterium and regular protium, heavy water exhibits many anomalous properties. The radioisotope tritium can also form tritiated water in much the"
"Hydrogen Hydrogen is a chemical element with symbol H and atomic number 1. With a standard atomic weight of , hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. Non-remnant stars are mainly composed of hydrogen in the plasma state. The most common isotope of hydrogen, termed ""protium"" (name rarely used, symbol H), has one proton and no neutrons. The universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless,"
"up to 3.1 g·cm can be adjusted . Adding parts of pulverulent Tungsten carbide increases the density to 4.6 g·cm. Heavy liquid A heavy liquid is a solution or liquid chemical substance with a high density and a relatively low viscosity. Heavy liquids are often used for determination of density in mineralogy, for density gradient centrifugation and for separating mixtures. Common applications of heavy liquids include: The classical heavy liquids like 1,1,2,2-tetrabromoethane (""Muthmanns solution""), potassium tetraiodomercurate(II) (""Thoulets solution""), bromoform or diiodomethane which are used in mineralogy are very toxic. These toxic chemicals are avoided today in consideration of the fact"
"or uranium in the latter case). Definition and usage Toxicity and biological role Formation Uses Heavy metals Heavy metals are generally defined as metals with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context. In metallurgy, for example, a heavy metal may be defined on the basis of density, whereas in physics the distinguishing criterion might be atomic number, while a chemist would likely be more concerned with chemical behaviour. More specific definitions have been published, but none of these have been widely accepted. The definitions"
"thought to contain a lot of liquid metallic hydrogen, which may be responsible for their observed powerful magnetic fields. Metallic hydrogen Metallic hydrogen is a phase of hydrogen in which it behaves like an electrical conductor. This phase was predicted in 1935 on theoretical grounds by Eugene Wigner and Hillard Bell Huntington. At high pressure and temperatures, metallic hydrogen can exist as a liquid rather than a solid, and researchers think it is present in large quantities in the hot and gravitationally compressed interiors of Jupiter, Saturn, and in some exoplanets. Though often placed at the top of the alkali"
"Binary compounds of hydrogen Binary compounds of hydrogen are binary chemical compounds containing just hydrogen and one other chemical element. By convention all binary hydrogen compounds are called hydrides even when the hydrogen atom in it is not an anion. These hydrogen compounds can be grouped into several types. Binary hydrogen compounds in group 1 are the ionic hydrides (also called saline hydrides) wherein hydrogen is bound electrostatically. Because hydrogen is located somewhat centrally in an electronegative sense, it is necessary for the counterion to be exceptionally electropositive for the hydride to possibly be accurately described as truly behaving ionic."
"environments. ""High Temperature Hydrogen Attack"" does not rely on atomic hydrogen. At high temperature and high hydrogen partial pressure, hydrogen can diffuse into carbon steel alloys. In susceptible alloys, the hydrogen combines with carbon within the alloy and forms methane. The methane molecules create a pressure buildup in the metal lattice voids, which leads to embrittlement and even cracking of the metal. Sulfidic corrosion, also known as sulfidation, is the term used for high temperature corrosion (above 450F / above approx. 260°C) of steel in contact with sulfur (Fe reacts with S to form FeS). Sulfide stress cracking Sulfide stress"
"simply added to the name of the ionic compound. Thus, for hydrogen chloride, the IUPAC name would be aqueous hydrogen chloride. The prefix ""hydro-"" is added only if the acid is made up of just hydrogen and one other element. Classical naming system: The strength of an acid refers to its ability or tendency to lose a proton. A strong acid is one that completely dissociates in water; in other words, one mole of a strong acid HA dissolves in water yielding one mole of H and one mole of the conjugate base, A, and none of the protonated acid"
"such materials the hydrogen is bonded with significant covalent character to the second metal or metalloid atoms. In general, complex metal hydrides have the formula MM'H, where M is an alkali metal cation or cation complex and M' is a metal or metalloid. Well known examples feature group 13 elements, especially boron and aluminium including sodium aluminium hydride, NaAlH (also known as sodium alanate), lithium aluminum hydride, LiAlH, and lithium borohydride, (LiBH). Complex metal hydrides are often soluble in etherial solvents. Other complex metal hydrides are numerous. Illustrative examples include the salts [MgBr(THF)]FeH and KReH. Complex metal hydride Complex metal"
"vehicles. AlH contains up to 10% hydrogen by weight, corresponding to 148g/L, twice the density of liquid H. Unfortunately, AlH is not a reversible carrier of hydrogen. It is a potential additive to rocket fuel and in explosive and pyrotechnic compositions. Aluminium hydride is not spontaneously flammable, but it is highly reactive, similar to lithium aluminium hydride. Aluminium hydride decomposes in air and water. Violent reactions occur with both. With care AlH can be handled safely in air, thought to be a result of a protective layer of aluminium oxide. Aluminium hydride Aluminium hydride (also known as alane or alumane)"
"odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H. Since hydrogen readily forms covalent compounds with most nonmetallic elements, most of the hydrogen on Earth exists in molecular forms such as water or organic compounds. Hydrogen plays a particularly important role in acid–base reactions because most acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) when it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H. The hydrogen cation is written as"
"Heavy metals Heavy metals are generally defined as metals with relatively high densities, atomic weights, or atomic numbers. The criteria used, and whether metalloids are included, vary depending on the author and context. In metallurgy, for example, a heavy metal may be defined on the basis of density, whereas in physics the distinguishing criterion might be atomic number, while a chemist would likely be more concerned with chemical behaviour. More specific definitions have been published, but none of these have been widely accepted. The definitions surveyed in this article encompass up to 96 out of the 118 known chemical elements;"
"Hydrogen astatide Hydrogen astatide, also known as astatine hydride, astatane, or astidohydrogen, is a chemical compound with the chemical formula , consisting of an astatine atom covalently bonded to a hydrogen atom. It thus is a hydrogen halide. This chemical compound can dissolve in water to form hydroastatic acid, which exhibits properties very similar to the other four binary acids, and is in fact the strongest among them. However, it is limited in use due to its ready decomposition into elemental hydrogen and astatine, as well as the short half-life of the various isotopes of astatine. Because the atoms have"
"complexes for the sake of completeness. As with the above table, only the complexes with the most complete valence is shown, to the negligence of the most stable complex. A molecular hydride may be able to bind to hydrogen molecules acting as a ligand. The complexes are termed non-classical covalent hydrides. These complexes contain more hydrogen than the classical covalent hydrides, but are only stable at very low temperatures. They may be isolated in inert gas matrix, or as a cryogenic gas. Others have only been predicted using computational chemistry. Hydrogen has a highly variable solubility in the elements. When"
"is a renewable fuel. Hydrogen is mainly used for the conversion of heavy petroleum fractions into lighter ones via the process of hydrocracking and other processes (dehydrocyclization and the aromatization process). It is also required for cleaning fossil fuels via hydrodesulfurization. Hydrogen is mainly used for the production of ammonia via Haber process. In this case, the hydrogen is produced ""in situ"". Ammonia is the major component of most fertilizers. Earlier it was common to vent the surplus hydrogen off, nowadays the process systems are balanced with hydrogen pinch to collect hydrogen for further use. Hydrogen may be used in"
"sulfuric acid (HSO). All straight-chain hydrogen chalcogenides follow the formula HX. Higher hydrogen polyoxides than HO are not stable. Trioxidane, with three oxygen atoms, is a transient unstable intermediate in several reactions. The next two in the oxygen series, hydrogen tetroxide and hydrogen pentoxide, have also been synthesized and found to be highly reactive. An alternative structural isomer of trioxidane, in which the two hydrogen atoms are attached to the central oxygen of the three-oxygen chain rather than one on each end, has been examined computationally. Beyond HS and HS, many higher polysulfanes HS (""n"" = 3–8) are known as"
"to hydrogen bonding. Non-classical hydrides are those in which extra hydrogen molecules are coordinated as a ligand on the central atoms. These are very unstable but some have been shown to exist. Polyhydrides or superhydrides are compounds in which the number of hydrogen atoms exceed the valency of the combining atom. These may only be stable under extreme pressure, but may be high temperature superconductors, such as HS, superconducting at up to 203 K. Polyhydrides are actively studied with the hope of discovering a room temperature superconductor. The relative stability of binary hydrogen compounds and alloys at standard temperature and"
"Semiheavy water Semiheavy water is the result of replacing one of the protium in light water to deuterium. It exists whenever there is water with light hydrogen (protium, H) and deuterium (D or H) in the mix. This is because hydrogen atoms (hydrogen-1 and deuterium) are rapidly exchanged between water molecules. Water containing 50% H and 50% D in its hydrogen contains about 50% HDO and 25% each of HO and DO, in dynamic equilibrium. In regular water, about 1 molecule in 3,200 is HDO (one hydrogen in 6,400 is D). By comparison, heavy water DO occurs at a proportion"
"Hydrogen chalcogenide Hydrogen chalcogenides (also chalcogen hydrides or hydrogen chalcides) are binary compounds of hydrogen with chalcogen atoms (elements of group 16: oxygen, sulfur, selenium, tellurium, and polonium). Water, the first chemical compound in this series, contains one oxygen atom and two hydrogen atoms, and is the most common compound on the Earth's surface. The most important series, including water, has the chemical formula HX, with X representing any chalcogen. They are therefore triatomic. They take on a bent structure and as such are polar molecules. Water is an essential compound to life on Earth today, covering 70.9% of the"
"High-test peroxide High-test peroxide or HTP is a highly concentrated (85 to 98 percent) solution of hydrogen peroxide, with the remainder predominantly made up of water. In contact with a catalyst, it decomposes into a high-temperature mixture of steam and oxygen, with no remaining liquid water. It was used as a propellant of HTP rockets and torpedoes, and has been used for high-performance vernier engines. Hydrogen peroxide works best as a propellant in extremely high concentrations – roughly over 70%. Although any concentration of peroxide will generate some hot gas (oxygen plus some steam), at concentrations above approximately 67%, the"