|
Tellurous Acid ion. It is usually prepared as an aqueous solution where it acts as a weak acid. Tellurous acid is an inorganic compound with the formula H2TeO3. It is the oxoacid of tellurium(IV). This compound is not well characterized. An alternative way of writing its formula is (HO)2TeO. In principle, tellurous acid would form by treatment of tellurium dioxide with water, that is by hydrolysis. The related conjugate base is well known in the form of several salts such as potassium hydrogen tellurite, KHTeO3. Properties In contrast to the analogous compound selenous acid, tellurous acid is only metastable. Most tellurite salts contain the ion. Oxidation of its aqueous solution with hydrogen peroxide gives the tellurate In chemistry tellurate is a compound containing an oxyanion of tellurium where tellurium has an oxidation number of +6. In the naming of inorganic compounds it is a suffix that indicates a polyatomic anion with a central tellurium atom. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellurite (ion)
The tellurite ion is . A tellurite (compound), for example sodium tellurite, is a compound that contains this ion. They are typically colorless or white salts, which in some ways are comparable to sulfite. A mineral with the formula TeO2 is called tellurite. Structure and reactions Tellurite dianion is pyramidal, like selenite and sulfite. The anion has C3v symmetry. Tellurites can be reduced to elemental tellurium by electrolysis or a strong reducing agent. When fused with nitrate salts, tellurite salts oxidize to tellurates (). Upon acidification of aqueous solutions of tellurite salts, solid hydrated tellurium dioxide (TeO2) precipitates. This reaction allows the separation of tellurium from selenium since selenous acid remains soluble at low pH. The intermediate in the protonation occurs at oxygen to give eO2(OH)sup>−. Uses Potassium tellurite (K2TeO3) is used together with agar as part of a selective medium for growth of some bacteria (Clauberg medium). Coryneba ... [...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] |
Sulfurous Acid
Sulfurous acid (also sulfuric(IV) acid, sulphurous acid (UK), sulphuric(IV) acid (UK)) is the chemical compound with the formula . There is no evidence that sulfurous acid exists in solution, but the molecule has been detected in the gas phase. The conjugate bases of this elusive acid are, however, common anions, bisulfite (or hydrogen sulfite) and sulfite. Sulfurous acid is an intermediate species in the formation of acid rain from sulfur dioxide. Raman spectra of solutions of sulfur dioxide in water show only signals due to the molecule and the bisulfite ion, . The intensities of the signals are consistent with the following equilibrium: 17O NMR spectroscopy provided evidence that solutions of sulfurous acid and protonated sulfites contain a mixture of isomers, which is in equilibrium: Attempts to concentrate the solutions of sulfurous acid simply reverses the equilibrium, producing sulfur dioxde and water vapor. A clathrate with the formul a has been crystallised. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Tellurite
Sodium tellurite is an inorganic tellurium compound with formula Na2TeO3. It is a water-soluble white solid and a weak reducing agent. Sodium tellurite is an intermediate in the extraction of the element, tellurium; it is a product obtained from anode slimes and is a precursor to tellurium. Preparation The main source of tellurium is from copper anode slimes, which contain precious metals as well as various tellurides. These slimes are roasted with sodium carbonate and oxygen to produce sodium tellurite. :Ag2Te + Na2CO3 + O2 → 2Ag + Na2TeO3 + CO2 (400–500 °C) This is a reaction with silver telluride. The telluride is oxidized to tellurite and the silver(I) is reduced to silver. Purification The electrolysis of a tellurite solution yields purified tellurium. :Anode: 4OH− → 2H2O + O2 + 4e− :Cathode: TeO32− + 3H2O + 4e− → Te + 6OH− Structure and properties Tellurium has properties similar to sulfur and selenium. In the anhydrous form Na2TeO3 the tellurium at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telluric Acid
Telluric acid is a chemical compound with the formula , often written as . It is a white crystalline solid made up of octahedral molecules which persist in aqueous solution. In the solid state, there are two forms, rhombohedral and monoclinic, and both contain octahedral molecules, containing one hexavalent tellurium (Te) atom in the +6 oxidation state, attached to six hydroxyl (–OH) groups, thus, it can be called tellurium(VI) hydroxide. Telluric acid is a weak acid which is dibasic, forming tellurate salts with strong bases and hydrogen tellurate salts with weaker bases or upon hydrolysis of tellurates in water.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. . It is used as tellurium-source in the synthesis of oxidation catalysts. Preparation Telluric acid is formed by the oxidation of tellurium or tellurium dioxide with a powerful oxidising agent such as hydrogen peroxide, chromium trioxide or sodium peroxide. : Crystallization of tellur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenic Acid
Selenic acid is the inorganic compound with the formula . It is an oxoacid of selenium, and its structure is more accurately described as . It is a colorless compound. Although it has few uses, its derivative sodium selenate is used in the production of glass and animal feeds.Bernd E. Langner "Selenium and Selenium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim. . Structure and bonding The molecule is tetrahedral, as predicted by VSEPR theory. The Se–O bond length is 161 pm. In the solid state, it crystallizes in an orthorhombic structure. Preparation It is prepared by oxidising selenium compounds in lower oxidation states. One method involves the oxidation of selenium dioxide with hydrogen peroxide: : Unlike the production sulfuric acid by hydration of sulfur trioxide, the hydration of selenium trioxide is an impractical method. Instead, selenic acid may also be prepared by the oxidation of selenous acid () with halogens, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfuric Acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formula . It is a colorless, odorless and viscous liquid that is miscible with water. Pure sulfuric acid does not exist naturally on Earth due to its strong affinity to water vapor; it is hygroscopic and readily absorbs water vapor from the air. Concentrated sulfuric acid is highly corrosive towards other materials, from rocks to metals, since it is an oxidant with powerful dehydrating properties. Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid, but to the contrary dehydrates sulfuric acid to sulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus the reverse procedure of adding water to the acid should not be performed since the heat released may boi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inorganic Compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation. Some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon (graphite, diamond, buckminsterfullerene, etc.), carbon monoxide, carbon dioxide, carbides, and the following salts of inorganic anions: carbonates, cyanides, cyanates, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms; describing a chemical as inorganic does not necessarily mean that it does not occur within living things. History Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and ''plus'' (+) and ''minus'' (−) signs. These are limited to a single typographic line of symbols, which may include Subscript and superscript, subscripts and superscripts. A chemical formula is not a chemical nomenclature, chemical name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulae can fully specify the structure of only the simplest of molecules and chemical substances, and are generally more limited in power than chemical names and structural formulae. The simplest types of chemical formulae are called ''empirical formulae'', which use letters and numbers ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxoacid
An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce the H+ cation and the anion of the acid. Description Under Lavoisier's original theory, all acids contained oxygen, which was named from the Greek ὀξύς (''oxys'': acid, sharp) and the root -γενής (''-genes'': creator). It was later discovered that some acids, notably hydrochloric acid, did not contain oxygen and so acids were divided into oxo-acids and these new hydroacids. All oxyacids have the acidic hydrogen bound to an oxygen atom, so bond strength (length) is not a factor, as it is with binary nonmetal hydrides. Rather, the electronegativity of the central atom and the number of oxygen atoms determine oxyacid acidity. For oxyacids with the same central atom, acid strength increases with the number of oxygen atoms attache ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellurium Dioxide
Tellurium dioxide (TeO2) is a solid oxide of tellurium. It is encountered in two different forms, the yellow orthorhombic mineral tellurite, β-TeO2, and the synthetic, colourless tetragonal (paratellurite), α-TeO2. Most of the information regarding reaction chemistry has been obtained in studies involving paratellurite, α-TeO2.W.R.McWhinnie (1995) ''Tellurium - Inorganic chemistry'' Encyclopedia of Inorganic Chemistry Ed. R. Bruce King (1994) John Wiley & Sons Preparation Paratellurite, α-TeO2, is produced by reacting tellurium with O2: :Te + O2 → TeO2 An alternative preparation is to dehydrate tellurous acid, H2TeO3, or to thermally decompose basic tellurium nitrate, Te2O4·HNO3, above 400 °C. Physical properties The longitudinal speed of sound in Tellurium dioxide is at around room temperature. Chemical properties TeO2 is barely soluble in water and soluble in strong acids and alkali metal hydroxides. It is an amphoteric substance and therefore can act both ... [...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] |
