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Hypervalent
In chemistry, a hypervalent molecule (the phenomenon is sometimes colloquially known as expanded Octet rule, octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells. Phosphorus pentachloride (), sulfur hexafluoride (), chlorine trifluoride (), the chlorite () ion in chlorous acid and the triiodide () ion are examples of hypervalent molecules. Definitions and nomenclature Hypervalent molecules were first formally defined by Jeremy I. Musher in 1969 as molecules having central atoms of group 15–18 in any valence (chemistry), valence other than the lowest (i.e. 3, 2, 1, 0 for Groups 15, 16, 17, 18 respectively, based on the octet rule). Several specific classes of hypervalent molecules exist: * Hypervalent iodine compounds are useful reagents in organic chemistry (e.g. Dess–Martin periodinane) * Tetra-, penta- and hexavalent phosphorus, silicon, and sulfur compounds (e.g. PCl5, PF5, SF6, sulfuranes an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypervalent Iodine
Unlike its lighter congeners, the halogen iodine forms a number of stable organic compounds, in which iodine exhibits higher formal oxidation states than −1 or coordination number exceeding 1. These are the hypervalent organoiodines, often called iodanes after the IUPAC rule used to name them. These iodine compounds are hypervalent because the iodine atom formally contains in its valence shell more than the 8 electrons required for the octet rule. Hypervalent iodine oxyanions are known for oxidation states +1, +3, +5, and +7; organic analogues of these moieties are known for each oxidation state except +7. In terms of chemical behavior, λ3 and λ5iodanes are generally oxidizing and/or electrophilic species. They have been widely applied towards those ends in organic synthesis. Nomenclature Several different naming conventions are in use for the hypervalent organoiodines. All begin with nonstandard formal charge assignments. In iodane chemistry, carbon is consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthony Joseph Arduengo III
Anthony Joseph Arduengo III is Professor of the Practice at the Georgia Institute of Technology, Saxon Professor Emeritus of Chemistry at the University of Alabama, adjunct professor at the Institute for Inorganic Chemistry of Braunschweig University of Technology in Germany, and co-founder of the ''StanCE'' coalition for sustainable chemistry based on woody biomassXylochemistry. He is notable for his work on chemical compounds with unusual valence (chemistry), valency, especially in the field of stable carbene research. Early life Anthony "Bo" Arduengo was born in 1952 in Tampa, Florida. He grew up in the Atlanta, Georgia (U.S. state), Georgia area. His father was a pressman and mechanic with the ''Atlanta Journal-Constitution'' and instilled his son with an interest and skill for all things mechanical and scientific. By the age of 16, he and his father had built his first car from miscellaneous parts. The car was registered as street-legal and road-worthy. With some re-engineeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Octet Rule
The octet rule is a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas. The rule is especially applicable to carbon, nitrogen, oxygen, and the halogens; although more generally the rule is applicable for the s-block and p-block of the periodic table. Other rules exist for other elements, such as the duplet rule for hydrogen and helium, and the 18-electron rule for transition metals. The valence electrons in molecules like carbon dioxide (CO₂) can be visualized using a Lewis electron dot diagram. In covalent bonds, electrons shared between two atoms are counted toward the octet of both atoms. In carbon dioxide each oxygen shares four electrons with the central carbon, two (shown in red) from the oxygen itself and two (shown in black) from the carbon. All four of these electrons are counted in both the carbon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valence (chemistry)
In chemistry, the valence (US spelling) or valency (British spelling) of an atom is a measure of its combining capacity with other atoms when it forms chemical compounds or molecules. Valence is generally understood to be the number of chemical bonds that each atom of a given chemical element typically forms. Double bonds are considered to be two bonds, triple bonds to be three, quadruple bonds to be four, quintuple bonds to be five and sextuple bonds to be six. In most compounds, the valence of hydrogen is 1, of oxygen is 2, of nitrogen is 3, and of carbon is 4. Valence is not to be confused with the related concepts of the coordination number, the oxidation state, or the number of valence electrons for a given atom. Description The valence is the combining capacity of an atom of a given element, determined by the number of hydrogen atoms that it combines with. In methane, carbon has a valence of 4; in ammonia, nitrogen has a valence of 3; in water, oxygen has a valence of 2; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Cullen Martin
James Cullen Martin (January 14, 1928 – April 20, 1999) was an American chemist. Known in the field as "J.C.", he specialized in physical organic chemistry with an emphasis on main group element chemistry. Martin received his undergraduate and master's degree at Vanderbilt University. His PhD work was conducted with Paul Bartlett at Harvard. Most of his professional career was at the University of Illinois at Urbana-Champaign, where he was a colleague of Roger Adams, Speed Marvel, David Y. Curtin, Nelson J. Leonard, and Reynold C. Fuson. Late in his career, he moved back to Vanderbilt, but soon succumbed to poor health. Professor Martin is best known for his work on bonding of main group elements. He is responsible for the hexafluorocumyl alcohol derived "Martin" bidentate ligand and a tridentate analog. With his doctoral student Daniel Benjamin Dess, he invented the Dess–Martin periodinane that is used for selective oxidation of alcohols. He is also known for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphorus Pentachloride
Phosphorus pentachloride is the chemical compound with the formula . It is one of the most important phosphorus chlorides/oxychlorides, others being and . finds use as a chlorinating reagent. It is a colourless, water-sensitive solid, although commercial samples can be yellowish and contaminated with hydrogen chloride. Structure The structures for the phosphorus chlorides are invariably consistent with VSEPR theory. The structure of depends on its environment. Gaseous and molten is a neutral molecule with trigonal bipyramidal geometry and (''D''3h) symmetry. The hypervalent nature of this species (as well as of , see below) can be explained with the inclusion of non-bonding molecular orbitals (molecular orbital theory) or resonance (valence bond theory). This trigonal bipyramidal structure persists in nonpolar solvents, such as and . In the solid state is an ionic compound called tetrachlorophosphonium hexachlorophosphate formulated . In solutions of polar solvents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfur Hexafluoride
Sulfur hexafluoride or sulphur hexafluoride ( British spelling) is an inorganic compound with the formula SF6. It is a colorless, odorless, non-flammable, and non-toxic gas. has an octahedral geometry, consisting of six fluorine atoms attached to a central sulfur atom. It is a hypervalent molecule. Typical for a nonpolar gas, is poorly soluble in water but quite soluble in nonpolar organic solvents. It has a density of 6.12 g/L at sea level conditions, considerably higher than the density of air (1.225 g/L). It is generally stored and transported as a liquefied compressed gas. has 23,500 times greater global warming potential (GWP) than as a greenhouse gas (over a 100-year time-frame) but exists in relatively minor concentrations in the atmosphere. Its concentration in Earth's troposphere reached 12.06 parts per trillion (ppt) in February 2025, rising at 0.4 ppt/year. The increase since 1980 is driven in large part by the expanding electric power sector, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorine Trifluoride
Chlorine trifluoride is an interhalogen compound with the formula . It is a colorless, poisonous, corrosive, and extremely reactive gas that condenses to a pale-greenish yellow liquid, the form in which it is most often sold (pressurized at room temperature). It is notable for its extreme oxidation properties. The compound is primarily of interest in plasmaless cleaning and etching operations in the semiconductor industry, in nuclear reactor fuel processing, historically as a component in rocket fuels, and various other industrial operations owing to its corrosive nature. Preparation, structure, and properties It was first reported in 1930 by Ruff and Krug who prepared it by fluorination of chlorine; this also produced chlorine monofluoride (ClF) and the mixture was separated by distillation. : Several hundred tons are produced annually. The molecular geometry of is approximately T-shaped, with one short bond (1.598 Å) and two long bonds (1.698 Å). This structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Jay Kochi
Jay Kazuo Kochi (高知 和夫, ''Kōchi Kazuo'', 1927–2008) was an American physical organometallic chemist who held lectureship at Harvard University, and faculty positions at Case Institute of Technology, 1962–1969, (now Case Western Reserve University), Indiana University, 1969 to 1984, and the University of Houston, 1984 to 2008. Early life and education Kochi was born to Japanese immigrant parents on May 17, 1927, in Los Angeles, California, where he and his family had lived until he and his family were imprisoned at the Gila River War Relocation Center in 1942 just after the United States entered the Second World War and Executive Order 9066 was signed. After the war, Kochi and his family returned to California and Kochi later attended UCLA. Kochi received his Bachelor of Science degree from the University of California, Los Angeles in 1949 and his Ph.D. at Iowa State University in 1952 with George S. Hammond and Henry Gilman as advisors. He then spent short stints a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
