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Ferrous Hydroxide
Iron(II) hydroxide or ferrous hydroxide is an inorganic compound with the formula Fe(OH)2. It is produced when iron(II) salts, from a compound such as iron(II) sulfate, are treated with hydroxide ions. Iron(II) hydroxide is a white solid, but even traces of oxygen impart a greenish tinge. The air-oxidised solid is sometimes known as "green rust". Preparation and reactions Iron(II) hydroxide is poorly soluble in water (1.43 × 10−3 g/ L), or 1.59 × 10−5 mol/L. It precipitates from the reaction of iron(II) and hydroxide salts:H. Lux "Iron(II) Hydroxide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1498. :FeSO4 + 2 NaOH → Fe(OH)2 + Na2SO4 If the solution is not deoxygenated and iron not totally reduced in Fe(II), the precipitate can vary in colour starting from green to reddish brown depending on the iron(III) content. Iron(II) ions are easily substituted by iron(III) ions produced by its progressiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron(II) Oxide
Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists of hydrated iron(III) oxide (ferric oxide). Iron(II) oxide also refers to a family of related non-stoichiometric compounds, which are typically iron deficient with compositions ranging from Fe0.84O to Fe0.95O. Preparation FeO can be prepared by the thermal decomposition of iron(II) oxalate. :FeC2O4 → FeO + CO2 + CO The procedure is conducted under an inert atmosphere to avoid the formation of iron(III) oxide (Fe2O3). A similar procedure can also be used for the synthesis of manganous oxide and stannous oxide. Stoichiometric FeO can be prepared by heating Fe0.95O with metallic iron at 770 °C and 36 kbar.Wells A.F. (1984) ''Structural Inorganic Chemistry'' 5th edition Oxford University Press Reactions FeO is therm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystal Lattice
In geometry and crystallography, a Bravais lattice, named after , is an infinite array of discrete points generated by a set of discrete translation operations described in three dimensional space by : \mathbf = n_1 \mathbf_1 + n_2 \mathbf_2 + n_3 \mathbf_3, where the ''ni'' are any integers, and a''i'' are ''primitive translation vectors'', or ''primitive vectors'', which lie in different directions (not necessarily mutually perpendicular) and span the lattice. The choice of primitive vectors for a given Bravais lattice is not unique. A fundamental aspect of any Bravais lattice is that, for any choice of direction, the lattice appears exactly the same from each of the discrete lattice points when looking in that chosen direction. The Bravais lattice concept is used to formally define a ''crystalline arrangement'' and its (finite) frontiers. A crystal is made up of one or more atoms, called the ''basis'' or ''motif'', at each lattice point. The ''basis'' may consist of atoms, mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wetland
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The primary factor that distinguishes wetlands from terrestrial land forms or Body of water, water bodies is the characteristic vegetation of aquatic plants, adapted to the unique anoxic hydric soils. Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods for assessing wetland functions, wetland ecological health, and general wetland condition have been developed for many regions of the world. These methods have contributed to wetland conservation partly by raising public awareness of the functions some wetlands provide. Wetlands occur naturally on every continent. The water in wetlands is either freshwater, brackish or seawater, saltwater. The main w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenous Acid
Selenous acid (or selenious acid) is the chemical compound with the formula . Structurally, it is more accurately described by . It is the principal oxoacid of selenium; the other being selenic acid. Formation and properties Selenous acid is analogous to sulfurous acid, but it is more readily isolated. Selenous acid is easily formed upon the addition of selenium dioxide to water. As a crystalline solid, the compound can be seen as pyramidal molecules that are interconnected with hydrogen bonds. In solution it is a diprotic acid: : (p''K''a = 2.62) : (p''K''a = 8.32) It is moderately oxidizing in nature, but kinetically slow. In 1 M : : (''E''o = +0.74 V) In 1 M : : (''E''o = −0.37 V) Selenous acid is hygroscopic. Uses The major use is in protecting and changing the color of steel, especially steel parts on firearms. The so-called cold-bluing process uses selenous acid, copper(II) nitrate, and nitric acid to change the color of the st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amakinite
Amakinite ( IMA symbol: Amk) is a semi transparent yellow-green hydroxide mineral belonging to the brucite group that was discovered in 1962. Its chemical formula is written as (Fe2+,Mg)(OH)2. It usually occurs in the form of splotchy, anhedral crystals forming within a group or structure in other minerals or rocks, such as kimberlite (occurring in diamond-rich eruptive pipe). Its composition is as follows: * Magnesium 5.82% Mg 9.66% MgO * Manganese 6.58% Mn 8.50% MnO * Iron 46.84% Fe 60.26% FeO * Hydrogen 2.42% H 21.58% * Oxygen 38.34% O Amakinite is slightly magnetic and was named for the Amakin Expedition, which prospected the diamond deposits of Yakutia in the Russian Far East The Russian Far East (russian: Дальний Восток России, r=Dal'niy Vostok Rossii, p=ˈdalʲnʲɪj vɐˈstok rɐˈsʲiɪ) is a region in Northeast Asia. It is the easternmost part of Russia and the Asian continent; and is admin .... References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring (hydrology)
A spring is a point of exit at which groundwater from an aquifer flows out on top of Earth's crust (pedosphere) and becomes surface water. It is a component of the hydrosphere. Springs have long been important for humans as a source of fresh water, especially in arid regions which have relatively little annual rainfall. Springs are driven out onto the surface by various natural forces, such as gravity and hydrostatic pressure. Their yield varies widely from a volumetric flow rate of nearly zero to more than for the biggest springs. Formation Springs are formed when groundwater flows onto the surface. This typically happens when the groundwater table reaches above the surface level. Springs may also be formed as a result of karst topography, aquifers, or volcanic activity. Springs also have been observed on the ocean floor, spewing hot water directly into the ocean. Springs formed as a result of karst topography create karst springs, in which ground water travels through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology. Typically, groundwater is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain soil moisture, perma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone Building With Pollution
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limestone c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenate
The selenate ion is . Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures. Unlike sulfate, selenate is a somewhat good oxidizer; it can be reduced to selenite or selenium. In strongly acidic conditions, the hydrogen selenate ion, , is formed. It corresponds to the selenic acid, H2SeO4, which is a strong acid and can in its concentrated form dissolve gold. The element selenium exhibits several valence states. Selenate is the least reduced, followed by selenite, and elemental selenium; selenide is even more reduced than elemental selenium. The valence state is an important factor to the toxicity of selenium. Selenate is the form required by organisms that need selenium as a micronutrient. These organisms have the ability to acquire, metabolize and excrete selenium. The level at which selenium becomes toxic varies from species to species and is related to other environmental factors like pH a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenite (ion)
Selenite refers to the anion with the chemical formula . It is the oxyanion of selenium. It is the selenium analog of the sulfite ion, . Thus selenite is pyramidal and selenium is assigned oxidation state +4. Selenite also refers to compounds that contains this ion, for example sodium selenite which is a common source of selenite. Selenite also refers to the esters of selenous acid, for example dimethyl selenite . Synthesis and reactions Selenite salts can be prepared by neutralizing solutions of selenous acid, which is generated by dissolving selenium dioxide in water. The process proceeds via the hydrogenselenite ion, . Selenite reacts with elemental sulfur to form thioselenate: : Most selenite salts can be formed by heating the metal oxide with selenium dioxide Selenium dioxide is the chemical compound with the formula SeO2. This colorless solid is one of the most frequently encountered compounds of selenium. Properties Solid SeO2 is a one-dimensional polymer, the chain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schikorr Reaction
The Schikorr reaction formally describes the conversion of the iron(II) hydroxide (Fe(OH)2) into iron(II,III) oxide (Fe3O4). This transformation reaction was first studied by Gerhard Schikorr. The global reaction follows: :\underset -> \underset + \underset + \underset It is of special interest in the context of the serpentinization, the formation of hydrogen by the action of water on a common mineral. Reaction mechanism The ''Schikorr reaction'' can be viewed as two distinct processes: * the wikt:anaerobic, anaerobic oxidation of two Fe(II) (Fe2+) into Fe(III) (Fe3+) by the protons of water. The redox, reduction of two water protons is accompanied by the production of molecular hydrogen (H2), and; * the loss of two water molecules from the iron(II) and iron(III) hydroxides giving rise to its dehydration and to the formation of a thermodynamically more stable phase iron(II,III) oxide. The global reaction can thus be decomposed in half redox reactions as follows: :2 (Fe2+ → Fe3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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