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Nickel Ammonium Chloride
Nickel is one of the metals that can form Tutton's salts. The singly charged ion can be any of the full range of potassium, rubidium, cesium, ammonium (NH4), or thallium. As a mineral the ammonium nickel salt, (NH4)2Ni(SO4)2, can be called nickelboussingaultite. With sodium, the double sulfate is nickelblödite Na2Ni(SO4)2 from the blödite family. Nickel can be substituted by other divalent metals of similar sized to make mixtures that crystallise in the same form. Nickel forms double salts with Tutton's salt structure with tetrafluoroberyllate with the range of cations of ammonia, potassium, rubidium, cesium, and thallium. Anhydrous salts of the formula M2Ni2(SO4)3, which can be termed metal nickel trisulfates, belong to the family of langbeinites. The known salts include (NH4)2Ni2(SO4)3, K2Ni2(SO4)3 and Rb2Ni2(SO4)3, and those of Tl and Cs are predicted to exist. Some minerals are double salts, for example Nickelzippeite Ni2(UO2)6(SO4)3(OH)10 · 16H2O which is isomorphic to c ...
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Tutton's Salts
Tutton's salts are a family of salts with the formula M2M'(SO4)2(H2O)6 (sulfates) or M2M'(SeO4)2(H2O)6 (selenates). These materials are double salts, which means that they contain two different cations, M+ and M'2+ crystallized in the same regular ionic lattice. The univalent cation can be potassium, rubidium, cesium, ammonium (NH4), deuterated ammonium (ND4) or thallium. Sodium or lithium ions are too small. The divalent cation can be magnesium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc or cadmium. In addition to sulfate and selenate, the divalent anion can be chromate (CrO42−), tetrafluoroberyllate (BeF42−), hydrogenphosphate (HPO42−) or monofluorophosphate (PO3F2−). Tutton's salts crystallize in the monoclinic space group ''P''21/''a''. The robustness is the result of the complementary hydrogen-bonding between the tetrahedral anions and cations as well their interactions with the metal aquo complex (H2O)6sup>2+. Examples and related compo ...
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Standard Conditions
Standard temperature and pressure (STP) are standard sets of conditions for experimental measurements to be established to allow comparisons to be made between different sets of data. The most used standards are those of the International Union of Pure and Applied Chemistry (IUPAC) and the National Institute of Standards and Technology (NIST), although these are not universally accepted standards. Other organizations have established a variety of alternative definitions for their standard reference conditions. In chemistry, IUPAC changed its definition of standard temperature and pressure in 1982: * Until 1982, STP was defined as a temperature of 273.15  K (0 °C, 32 °F) and an absolute pressure of exactly 1  atm (101.325  kPa). * Since 1982, STP has been defined as a temperature of 273.15  K (0 °C, 32 °F) and an absolute pressure of exactly 105  Pa (100 kPa, 1 bar). STP should not be confused with the standard state ...
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Phosphine
Phosphine ( IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane (). With traces of present, is spontaneously flammable in air ( pyrophoric), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is immediately dangerous to life or health at 50 ppm. Phosphine has a trigonal pyramidal structure. Phosphines are compounds that include and the organophosphines, which are derived from by substituting one or more hydrogen atoms with organic groups. They have the general formula . Phosphanes are saturated phosphorus hydrides of the form , such as triphosphane. Phosphine, PH3, is the smallest of the phosphines and the smallest of the phosphanes. History Philippe Gengembre (1764–1838), a student of Lavo ...
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Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia i ...
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Fractional Crystallization (chemistry)
In chemistry, fractional crystallization is a method of refining substances based on differences in their solubility. It fractionates via differences in crystallization (forming of crystals). If a mixture of two or more substances in solution are allowed to crystallize, for example by allowing the temperature of the solution to decrease or increase, the precipitate will contain more of the least soluble substance. The proportion of components in the precipitate will depend on their solubility products. If the solubility products are very similar, a cascade process will be needed to effectuate a complete separation. This technique is often used in chemical engineering to obtain pure substances, or to recover saleable products from waste solutions. Fractional crystallization can be used to separate solid-solid mixtures. An example of this is separating KNO3 and KClO3.Viraf.J.Dalal Class 6/7 book See also * Cold Water Extraction * Fractional crystallization (geology) * ...
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Ferromagnetism
Ferromagnetism is a property of certain materials (such as iron) which results in a large observed magnetic permeability, and in many cases a large magnetic coercivity allowing the material to form a permanent magnet. Ferromagnetic materials are the familiar metals noticeably attracted to a magnet, a consequence of their large magnetic permeability. Magnetic permeability describes the induced magnetization of a material due to the presence of an ''external'' magnetic field, and it is this temporarily induced magnetization inside a steel plate, for instance, which accounts for its attraction to the permanent magnet. Whether or not that steel plate acquires a permanent magnetization itself, depends not only on the strength of the applied field, but on the so-called coercivity of that material, which varies greatly among ferromagnetic materials. In physics, several different types of material magnetism are distinguished. Ferromagnetism (along with the similar effect ferrimagnetism ...
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Diperiodatonickelates
The periodatonickelates are a series of anions and salts of nickel complexed to the periodate anion. The diperiodatonickelates with nickel in the +4 oxidation state are powerful oxidising agents that are capable of oxidising bromate to perbromate. Sodium nickel periodate, NaNiIO6·0.5H2O and potassium nickel periodate, KNiIO6·0.5H2O were discovered in 1949 by P. Ray and B. Sarma. These double salts are coloured dark purple. The salts were made by oxidising nickel sulfate mixed with potassium periodate (or sodium periodate) with the alkali persulfate salt in boiling water. Similar solids exist for other alkalis such as RbNiIO6·0.5H2O ,CsNiIO6·0.5H2O and NH4NiIO6·0.5H2O. The crystalline salts are insoluble in water, acids or bases. Ozone can also be used as the oxidiser. The colour is due to absorbance of visible light shorter than 800 nm, with a peak at 540 nm. The crystal structure of all the solids has space group ''P''312. It contains layers of hexagon arrangemen ...
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Tetraiodonickelates
Tetraiodonickelate is a complex ion of nickel with four iodide atoms iI4sup>2− arranged in a tetrahedron. iI4sup>2− is red in solution. This colour is due to absorption around 530 nm and below 450 nm. Maximum light transmission is around 620 nm, which is red. A broad weak absorption in the near infrared is at 740 nm. The magnetic moment is anomalously low. A mixture of lithium iodide and nickel iodide in water or methanol can partition NiI42− ions into a cyclohexane-amine mixture. The solution formed is blood red. History Already in 1909 Cambi had noticed that a mixture of nickel iodide and sodium iodide Sodium iodide (chemical formula NaI) is an ionic compound formed from the chemical reaction of sodium metal and iodine. Under standard conditions, it is a white, water-soluble solid comprising a 1:1 mix of sodium cations (Na+) and iodide anions (I ... dissolved in acetone has a red colour. This red colour was due to the presence of tetraiodonickelat ...
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Tetrabromonickelates
The tetrabromonickelate anion contains a doubly-charged nickel atom (Ni2+) surrounded by four bromide ions in a tetrahedral arrangement. The formula is iBr4sup>2−. The anion combines with cations to form a series of salts called tetrabromonickelates. Strongly-coordinating solvents will displace one or more of the bromido ligands from the complex. Solvents that can dissolve tetrabromonickelate include acetone, acetonitrile, methyl ethyl ketone, and nitromethane. In the visible absorption spectrum there is a strong absorption band termed ''ν''3 near 710 nm which is caused by an electronic transition from 3T1(F) → 3T1(P). Another strong absorption in the near infrared called ''ν''2 near 770 nm is due to the 3T1(F) → 3A2(F) transition. Salts Dilithium tetrabromonickelate forms a dark blue solution in tetrahydrofuran. A mixture of lithium bromide and nickel bromide in water or methanol can transfer iBr4sup>2− ions into a cyclohexane-amine mixture. The ...
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Pleochroic
Pleochroism (from Greek πλέων, ''pléōn'', "more" and χρῶμα, ''khrôma'', "color") is an optical phenomenon in which a substance has different colors when observed at different angles, especially with polarized light. Background Anisotropic crystals will have optical properties that vary with the direction of light. The direction of the electric field determines the polarization of light, and crystals will respond in different ways if this angle is changed. These kinds of crystals have one or two optical axes. If absorption of light varies with the angle relative to the optical axis in a crystal then pleochroism results. Anisotropic crystals have double refraction of light where light of different polarizations is bent different amounts by the crystal, and therefore follows different paths through the crystal. The components of a divided light beam follow different paths within the mineral and travel at different speeds. When the mineral is observed at some an ...
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Tetrachloronickelates
Tetrachloronickelate is the metal complex with the formula iCl4sup>2−. Salts of the complex are available with a variety of cations, but a common one is tetraethylammonium. When concentrated lithium chloride and nickel chloride solution in water is mixed, only a pentaaquachloro complex is formed: i(H2O)5Clsup>+. However in other organic solvents, or molten salts the tetrachloronickelate ion can form. Nickel can be separated from such a solution in water or methanol, by partitioning it into a cyclohexane solution of amines. Organic ammonium salts of the type (R3NH)2 iCl4are often thermochromic (R = Me, Et, Pr). Near room temperature, these salts are yellow , but these solids become blue when heated to near 70 °C. The bright blue color is characteristic of tetrahedral iCl4sup>2−, the intensity being a consequence of the Laporte selection rule. The yellow color results from a polymer consisting of octahedral Ni centers. The corresponding tetrabromonickelates are als ...
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Blödite Family
The blodite group (or Blödite group) is a group of minerals with two (in most cases divalent) cations and two anions. The group includes blödite Na2Mg(SO4)2•4H2O, leonite K2Mg(SO4)2•4(H2O), anapaite Ca2Fe(PO4)2•4(H2O), schertelite (NH4)2Mg(PO3OH)2•4(H2O,) manganoblödite Na2Mn(SO4)2•4(H2O), cobaltoblödite Na2Co(SO4) 2•4(H2O), changoite Changoite is a rare zinc sulfate mineral with the formula Na2Zn(SO4)2·4H2O. Chagoite was discovered in the San Francisco Mine near Sierra Gorda, Antofagasta, Chile. The mineral is a zinc-analogue of blödite, cobaltoblödite, manganoblödite an ...Na2Zn(SO4)2•4(H2O) References Mineral groups {{mineral-stub ...
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