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Iodates
An iodate is the polyatomic anion with the formula . It is the most common form of iodine in nature, as it comprises the major iodine-containing ores. Iodate salts are often colorless. They are the salts of iodic acid. Structure Iodate is pyramidal in structure. The O–I–O angles range from 97° to 105°, somewhat smaller than the O–Cl–O angles in chlorate. Reactions Redox Iodate is one of several oxyanions of iodine, and has an oxidation number of +5. It participates in several redox reactions, such as the iodine clock reaction. Iodate shows no tendency to disproportionate to periodate and iodide, in contrast to the situation for chlorate. Iodate is reduced by sulfite: : Iodate oxidizes iodide in acidic conditions: : Similarly, chlorate oxidizes iodide to iodate: : Iodate is also obtained by reducing a periodate with a sulfide. The byproduct of the reaction is a sulfoxide. Acid-base Iodate is unusual in that it forms a strong hydrogen bond with its parent acid: : ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodic Acid
Iodic acid is a white water-soluble solid with the chemical formula . Its robustness contrasts with the instability of chloric acid and bromic acid. Iodic acid features iodine in the oxidation state +5 and is one of the most stable oxo-acids of the halogens. When heated, samples dehydrate to give iodine pentoxide. On further heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine. Preparation Iodic acid can be produced by oxidizing iodine with strong oxidizers such as nitric acid, chlorine, chloric acid or hydrogen peroxide, for example: : Iodic acid is also produced by the reaction of iodine monochloride with water: : Structure Iodic acid crystallises from acidic solution as orthorhombic α- in space group ''P''212121. The structure consists of pyramidal molecules linked by hydrogen bonding and intermolecular iodine-oxygen interactions. The I=O bond lengths are 1.81 Å while the I–OH distance is 1.89 Å. Several othe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Iodate
Calcium iodate is any of two inorganic compounds with the formula Ca(IO3)2(H2O)x, where x = 0 or 1. Both are colourless salts that occur as the minerals lautarite and bruggenite, respectively. A third mineral form of calcium iodate is dietzeite, a salt containing chromate with the formula Ca2(IO3)2CrO4. These minerals are the most common compounds containing iodate. Production and uses Lautarite, described as ''the'' most important mineral source of iodine, is mined in the Atacama Desert. Processing of the ore entails reduction of its aqueous extracts with sodium bisulfite to give sodium iodide. This comproportionation reaction is a major source of the sodium iodide. Calcium iodate can be produced by the anodic oxidation of calcium iodide or by passing chlorine into a hot solution of lime in which iodine has been dissolved. Calcium iodate is used as an iodine supplement in chicken feed. Ethylenediamine dihydroiodide (EDDI) is a more typical source of nutritional iodi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Iodate
Potassium iodate ( K I O3) is an ionic inorganic compound with the formula . It is a white salt that is soluble in water. Preparation and properties It can be prepared by reacting a potassium-containing base such as potassium hydroxide with iodic acid, for example: : HIO3 + KOH → KIO3 + H2O It can also be prepared by adding iodine to a hot, concentrated solution of potassium hydroxide: :3 I2 + 6 KOH → KIO3 + 5 KI + 3 H2O Or by fusing potassium iodide with potassium chlorate, bromate or perchlorate, the melt is extracted with water and potassium iodate is isolated from the solution by crystallization: :KI + KClO3 → KIO3 + KCl The analogous reaction with potassium hypochlorite is also possible:KI + 3KOCl → 3KCl + KIO3Conditions/substances to avoid include: heat, shock, friction, combustible materials, reducing materials, aluminium, organic compounds, carbon, hydrogen peroxide and sulfides. Applications Potassium iodate is sometimes used for iodination of tabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fluoroiodate
A fluorooxoiodate or fluoroiodate is a chemical compound or ion derived from iodate, by substituting some of the oxygen by fluorine. They have iodine in the +5 oxidation state. The iodine atoms have a stereochemically active lone-pair of electrons. Many are non-centrosymmetric, and are second harmonic generators (SHG) of intense light shining through them. They are under investigation as materials for non-linear optics In mathematics and science, a nonlinear system (or a non-linear system) is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathem ..., such as for generating ultraviolet light from visible or infrared lasers. Different ions include OF4sup>−, O2F2sup>−, O3Fsup>2−, and 2O5F2sup>2−. They are distinct from the iodate fluorides which are mixed anion compounds that do not have fluorine-iodine bonds. Properties Fluoroiodates are transparent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodine
Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a violet gas at . The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek , meaning 'violet'. Iodine occurs in many oxidation states, including iodide (I−), iodate (), and the various periodate anions. As the heaviest essential mineral nutrient, iodine is required for the synthesis of thyroid hormones. Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities. The dominant producers of iodine today are Chile and Japan. Due to its high atomic number and ease of attachment to organic compounds, it has also found favour as a non-toxic radiocontrast material. Because of the spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prophylaxis
Preventive healthcare, or prophylaxis, is the application of healthcare measures to prevent diseases.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental health and efficiency. Leavell, H. R., & Clark, E. G. (1979). Preventive Medicine for the Doctor in his Community (3rd ed.). Huntington, NY: Robert E. Krieger Publishing Company. Disease and disability are affected by environmental factors, genetic predisposition, disease agents, and lifestyle choices, and are dynamic processes that begin before individuals realize they are affected. Disease prevention relies on anticipatory actions that can be categorized as primal, primary, secondary, and tertiary prevention. Each year, millions of people die of preventable causes. A 2004 study showed that about half of all deaths in the United States in 2000 were due to preventable behaviors and exposures. Leading causes included cardiovascular disease, chron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homoassociation
In acid–base chemistry, homoassociation (an IUPAC term) is an association between a base and its conjugate acid through a hydrogen bond. Most commonly, homoassociation leads to the enhancement of the acidity of an acid by itself. The effect is accentuated at high concentrations, i.e. the ionization of an acid varies nonlinearly with concentration. This effect arises from the stabilization of the conjugate base by its formation of a hydrogen bond to the parent acid. A well known case is hydrofluoric acid, which is a significantly stronger acid when concentrated than when dilute due to the following equilibria: :2 HF \rightleftharpoons H2F+ + F− ( autoionization of HF) :HF + F− \rightleftharpoons HF2− (homoassociation) Overall: :3 HF \rightleftharpoons HF2− + H2F+ The bifluoride anion (HF2−) encourages the ionization of HF by stabilizing the F−. Thus, the usual ionization constant for hydrofluoric acid (10−3.15) understates the acidity of concentrate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Iodide
Potassium iodide is a chemical compound, medication, and dietary supplement. It is a medication used for treating hyperthyroidism, in radiation emergencies, and for protecting the thyroid gland when certain types of radiopharmaceuticals are used. It is also used for treating skin sporotrichosis and phycomycosis. It is a supplement used by people with low dietary intake of iodine. It is administered orally. Common side effects include vomiting, diarrhea, abdominal pain, rash, and swelling of the salivary glands. Other side effects include allergic reactions, headache, goitre, and depression. While use during pregnancy may harm the baby, its use is still recommended in radiation emergencies. Potassium iodide has the chemical formula K I. Commercially it is made by mixing potassium hydroxide with iodine. Potassium iodide has been used medically since at least 1820. It is on the World Health Organization's List of Essential Medicines. Potassium iodide is available as a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space-filling Model
In chemistry, a space-filling model, also known as a ''calotte model'', is a type of three-dimensional (3D) molecular model where the atoms are represented by spheres whose radii are proportional to the radii of the atoms and whose center-to-center distances are proportional to the distances between the atomic nuclei, all in the same scale. Atoms of different chemical elements are usually represented by spheres of different colors. Space-filling calotte models are also referred to as CPK models after the chemists Robert Corey, Linus Pauling, and Walter Koltun, who over a span of time developed the modeling concept into a useful form. They are distinguished from other 3D representations, such as the ball-and-stick and skeletal models, by the use of the "full size" space-filling spheres for the atoms. The models are tactile and manually rotatable. They are useful for visualizing the effective shape and relative dimensions of a molecule, and (because of the rotatability) the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioiodine
There are 40 known isotopes of iodine (53I) from 108I to 147I; all undergo radioactive decay except 127I, which is stable. Iodine is thus a monoisotopic element. Its longest-lived radioactive isotope, 129I, has a half-life of 16.14 million years, which is too short for it to exist as a primordial nuclide. Cosmogenic sources of 129I produce very tiny quantities of it that are too small to affect atomic weight measurements; iodine is thus also a mononuclidic element—one that is found in nature only as a single nuclide. Most 129I derived radioactivity on Earth is man-made, an unwanted long-lived byproduct of early nuclear tests and nuclear fission accidents. All other iodine radioisotopes have half-lives less than 60 days, and four of these are used as tracers and therapeutic agents in medicine - 123I, 124I, 125I, and 131I. All industrial use of radioactive iodine isotopes involves these four. The isotope 135I has a half-life less than seven hours, which is inconveniently sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iodized Salt
Iodised salt ( also spelled iodized salt) is table salt mixed with a minute amount of various iodine salts. The ingestion of iodine prevents iodine deficiency. Worldwide, iodine deficiency affects about two billion people and is the leading preventable cause of intellectual and developmental disabilities. Deficiency also causes thyroid gland problems, including endemic goitre. In many countries, iodine deficiency is a major public health problem that can be cheaply addressed by purposely adding small amounts of iodine to the sodium chloride salt. Iodine is a micronutrient and dietary mineral that is naturally present in the food supply in some regions, especially near sea coasts but is generally quite rare in the Earth's crust since iodine is a so-called heavy element, and abundance of chemical elements typically declines with greater atomic mass. Where natural levels of iodine in the soil are low and vegetables do not take up the iodine, iodine added to salt provides the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
