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Triiodide
In chemistry, triiodide usually refers to the triiodide ion, . This anion, one of the polyhalogen ions, is composed of three iodine atoms. It is formed by combining aqueous solutions of iodide salts and iodine. Some salts of the anion have been isolated, including thallium(I) triiodide (Tl+ 3sup>−) and ammonium triiodide ( H4sup>+ 3sup>−). Triiodide is observed to be a red colour in solution. Nomenclature Other chemical compounds with "triiodide" in their name may contain three iodide centers that are not bonded to each other as the triiodide ion, but exist instead as separate iodine atoms or iodide ions. Examples include nitrogen triiodide (NI3) and phosphorus triiodide (PI3), where individual iodine atoms are covalently bonded to a central atom. As some cations have the theoretical possibility to form compounds with both triiodide and iodide ions, such as ammonium, compounds containing iodide anions in a 3:1 stoichiometric ratio should only be referred to as triiodid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thallium Triiodide
Thallium triiodide, more precisely thallium(I) triiodide is a chemical compound of thallium and iodine with empirical formula . Unlike the other thallium trihalides, which contain thallium(III), is actually a thallium(I) salt containing thallium(I) cations and triiodide anions , and thus has the chemical formula . It is a black crystalline solid. An appreciation as to why is not oxidised to in the reaction: : can be gained by considering the standard reduction potentials of the half-cells which are: :;''Er''° = 1.252 :;''Er''° = 0.5355 The favoured reaction is therefore the reduction of to (1.252 > 0.5355). Using standard electrode potentials in this way must be done with caution as factors such as complex formation and solvation may affect the reaction. is no exception as it is possible to stabilise thallium(III) with excess forming the tetraiodothallate(III) ion (isoelectronic with the tetraiodomercurate anion and with lead(IV) iodide ). Structure and prepara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Triiodide
Nitrogen triiodide is an inorganic compound with the formula N I3. It is an extremely sensitive contact explosive: small quantities explode with a loud, sharp snap when touched even lightly, releasing a purple cloud of iodine vapor; it can even be detonated by alpha radiation. NI3 has a complex structural chemistry that is difficult to study because of the instability of the derivatives. Structure of NI3 and its derivatives Nitrogen triiodide was first characterized by Raman spectroscopy in 1990, when it was prepared by an ammonia-free route. Boron nitride reacts with iodine monofluoride in trichlorofluoromethane at −30 °C to produce pure NI3 in low yield: :BN + 3 IF → NI3 + BF3 NI3 is pyramidal (C3v molecular symmetry), as are the other nitrogen trihalides and ammonia. The material that is usually called "nitrogen triiodide" is prepared by the reaction of iodine with ammonia. When this reaction is conducted at low temperatures in anhydrous ammonia, the initial p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus Triiodide
Phosphorus triiodide (PI3) is an inorganic compound with the formula PI3. A red solid, it is too unstable to be stored for long periods of time; it is, nevertheless, commercially available. It is widely used in organic chemistry for converting alcohols to alkyl iodides and also serves as a powerful reducing agent. Properties Although PI3 is a pyramidal molecule, it has only a small molecular dipole because each P-I bond has almost no bond dipole moment. The P-I bond is also weak; PI3 is much less stable than PBr3 and PCl3, with a standard enthalpy of formation for PI3 of only −46 kJ/ mol (solid). The phosphorus atom has an NMR chemical shift of 178 ppm (downfield of H3PO4). Reactions Phosphorus triiodide reacts vigorously with water, producing phosphorous acid (H3PO3) and hydroiodic acid (HI), along with smaller amounts of phosphine and various P-P-containing compounds. Alcohols likewise form alkyl iodides, this providing the main use for PI3. PI3 is also a powerful r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Triiodide
Ammonium triiodide (NH4I3) is the salt of the ammonium cation with the triiodide anion. Sometimes the name ammonium triiodide is mistakenly used to refer to a different compound, nitrogen triiodide (NI3), or more precisely, the slightly more stable ammine In coordination chemistry, metal ammine complexes are metal complexes containing at least one ammonia () ligand. "Ammine" is spelled this way for historical reasons; in contrast, alkyl or aryl bearing ligands are spelt with a single "m". Almost al ..., NI3 · NH3. References Ammonium compounds Polyhalides Triiodides {{Inorganic-compound-stub ... [...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] |
Three-center Four-electron Bond
The 3-center 4-electron (3c–4e) bond is a model used to explain bonding in certain hypervalent molecules such as tetratomic and hexatomic interhalogen compounds, sulfur tetrafluoride, the xenon fluorides, and the bifluoride ion. It is also known as the Pimentel–Rundle three-center model after the work published by George C. Pimentel in 1951,Pimentel, G. C. The Bonding of Trihalide and Bifluoride Ions by the Molecular Orbital Method. ''J. Chem. Phys.'' 1951, ''19'', 446-448. which built on concepts developed earlier by Robert E. Rundle for electron-deficient bonding.Rundle, R. E. Electron Deficient Compounds. II. Relative Energies of "Half-Bonds". ''J. Chem. Phys.'' 1949, ''17'', 671–675. An extended version of this model is used to describe the whole class of hypervalent molecules such as phosphorus pentafluoride and sulfur hexafluoride as well as multi-center π-bonding such as ozone and sulfur trioxide. There are also molecules such as diborane (B2H6) and dial ... [...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] |
Rubidium Triiodide
Rubidium triiodide is an inorganic compound with the chemical formula RbI3. It is composed of Rb+ and . Preparation Rubidium triiodide can be obtained by heating rubidium iodide and iodine in aqueous solution: : RbI + I2 → RbI3 Properties Rubidium triiodide is an orthorhombic black crystal, isomorphic to caesium triiodide, with space group ''Pnma'', unit cell parameters ''a'' = 1090.8 pm, ''b'' = 665.5 pm, ''c'' = 971.1 pm. Upon heating to 270 °C, the rubidium triiodide decomposes into rubidium iodide and elemental iodine. It is soluble in ethanol and decomposes in ether In organic chemistry, ethers are a class of compounds that contain an ether group, a single oxygen atom bonded to two separate carbon atoms, each part of an organyl group (e.g., alkyl or aryl). They have the general formula , where R and R� .... Reactions It has long been believed that rubidium triiodide reacts further with iodine to form RbI7 and RbI9, but this has been refuted by recent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caesium Triiodide
Caesium triiodide is an inorganic compound, with the chemical formula of CsI3. It can be prepared by slow volatilization and crystallization of caesium iodide and iodine in aqueous ethanol solution. It can form precipitates with diazobenzene. It undergoes a phase transition In physics, chemistry, and other related fields like biology, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic Sta ... from Pnma to P-3c1 under high pressure, and its structure changes from layered to 3D. References {{Iodides Caesium compounds Polyhalides Iodides Triiodides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gallium(III) Iodide
Gallium(III) iodide is the inorganic compound with the formula Ga I3. A yellow hygroscopic solid, it is the most common iodide of gallium. In the chemical vapor transport method of growing crystals of gallium arsenide uses iodine as the transport agent. In the solid state, it exists as the dimer Ga2I6, with a diborane structure. When vaporized, its forms GaI3 molecules of D3h symmetry where the Ga–I distance is 2.458 Angstroms The angstrom (; ) is a unit of length equal to m; that is, one ten-billionth of a metre, a hundred-millionth of a centimetre, 0.1 nanometre, or 100 picometres. The unit is named after the Swedish physicist Anders Jonas Ångström (1814–1874) .... Gallium triiodide can be reduced with gallium metal to give a green-colored gallium(I) iodide. The nature of this species is unclear, but it is useful for the preparation of gallium(I) and gallium(II) compounds. See also * Gallium halides References Cited sources * Iodides Gallium compoun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
